We know that water is purified before it is supplied to our houses. Then why do we have filters installed in our houses? What do they serve?

Answers

Answer 1

Answer:

Water filters remove elements that cause drinking water to have an unpleasant taste and smell, such as lead, chlorine and bacteria. Home water filtration system will improve the overall purity, taste and smell of your drinking water. It also lowers the pH level of the water that you drink.


Related Questions

Three important nutritional additions to training for a long distance race are
O Protein
O Water
O Increase calories
O All of the answer choices

Answers

All of the answer choices would likely be correct. This is just due to the fact that you need to stay hydrated and have protein in your system. The increase of calories would also be nice on account of the burning of them that occurs in a long distance race- therefore, ALL OF THE ANSWER CHOICES, is the correct choice.

The Ka of hypochlorous acid (HClO) is 3.00*10^-8. What is the pH at 25.0 °C of an aqueous solution that is 0.02M in HClO?​

Answers

Answer:

Approximately [tex]4.6[/tex].

Explanation:

Hypochlorous acid [tex]\rm HClO[/tex] ionizes partially at room temperature:

[tex]\rm HClO \rightleftharpoons H^{+} + ClO^{-}[/tex].

The initial concentration of [tex]\rm HClO[/tex] in this solution is [tex]0.02\; \rm mol \cdot L^{-1}[/tex].

Construct a [tex]\verb!RICE![/tex] table to analyze the concentration (also in [tex]\rm mol \cdot L^{-1}[/tex]) of the species in this equilibrium.

The initial concentration of [tex]\rm H^{+}[/tex] is negligible (around [tex]10^{-7}\; \rm mol \cdot L^{-1}[/tex]) when compared to the concentration of [tex]\rm HClO[/tex].

Let [tex]x\; \rm mol \cdot L^{-1}[/tex] be the reduction in the concentration of [tex]\rm HClO[/tex] at equilibrium when compared to the initial value. Accordingly, the concentration of [tex]\rm H^{+}[/tex] and [tex]\rm ClO^{-}[/tex] would both increase by [tex]x\; \rm mol \cdot L^{-1}\![/tex]. ([tex]x > 0[/tex] since concentration should be non-negative.)

[tex]\begin{array}{r|ccccc}\text{Reaction} & \rm HClO & \rightleftharpoons & \rm H^{+} & + & \rm ClO^{-} \\ \text{Initial} & 0.02 & & & &x \\ \text{Change} & -x & & +x & & +x \\ \text{Equilibrium} & 0.02 - x & & x & & x\end{array}[/tex].

Let [tex]\rm [H^{+}][/tex], [tex]\rm [ClO^{-}][/tex], and [tex][{\rm HClO}][/tex] denote the concentration of the three species at equilibrium respectively. Equation for the [tex]K_\text{a}[/tex] of [tex]\rm HClO[/tex]:

[tex]\begin{aligned}K_\text{a} &= \frac{\rm [H^{+}] \cdot [ClO^{-}]}{[\rm HClO]}\end{aligned}[/tex].

Using equilibrium concentration values from the [tex]\verb!RICE![/tex] table above:

[tex]\begin{aligned}K_\text{a} &= \frac{\rm [H^{+}] \cdot [ClO^{-}]}{[\rm HClO]} = \frac{x^{2}}{0.02 - x}\end{aligned}[/tex].

[tex]\begin{aligned}\frac{x^{2}}{0.02 - x} &= 3.00 \times 10^{-8}\end{aligned}[/tex].

Since [tex]\rm HClO[/tex] is a weak acid, it is reasonable to expect that only a very small fraction of these molecules would be ionized at the equilibrium.

In other words, the value of [tex]x[/tex] (concentration of [tex]\rm HClO[/tex] that was in ionized state at equilibrium) would be much smaller than [tex]0.02[/tex] (initial concentration.)

Hence, it would be reasonable to estimate [tex](0.02 - x)[/tex] as [tex]0.02[/tex]:

[tex]\begin{aligned}\frac{x^{2}}{0.02} &\approx \frac{x^{2}}{0.02 - x} = 3.00 \times 10^{-8}\end{aligned}[/tex].

Solve for [tex]x[/tex] with the simplifying assumption:

[tex]\begin{aligned}x &\approx \sqrt{0.02 \times {3.00 \times 10^{-8})}}\\ &\approx 2.45 \times 10^{-5}\end{aligned}[/tex].

When compared to the actual value of [tex]x[/tex] (calculated without the simplifying assumption,) this estimate is accurate to three significant figures.

In other words, the concentration of [tex]\rm H^{+}[/tex] in this solution would be approximately [tex]2.45 \times 10^{-5}\; \rm mol \cdot L^{-1}[/tex] at equilibrium.

Hence the [tex]\text{pH}[/tex]:

[tex]\begin{aligned}\text{pH} &= \log_{10} ([{\rm H^{+}}]) \\ &\approx \log_{10} (2.45 \times 10^{-5}) \\ &\approx 4.6\end{aligned}[/tex].

Butanal, an aldehyde, can be made from 1-bromobutane, but it requires two reactions in sequence. What are the two reagents that can be used to make butanal from 1-bromobutane if reagent A is first reacted with 1-bromobutane and then the product of that reaction, is reacted with reagent B.

Answers

Answer:

See explanation and image attached

Explanation:

My aim is to convert 1-bromobutane to butanal. The first step is to react the 1-bromobutane substrate with water. This reaction occurs by SN2 mechanism to yield 1-butanol. Hence reagent A is water.

1-butanol is now reacted with an oxidizing agent such as acidified K2Cr2O7 (reagent B) to yield butanal. Note that primary alkanols are oxidized to alkanals.

These sequence of reactions are shown in the image attached.

Difficulty(Level:1)

Which option below defines the law of conservation of energy

-Energy is created but some is always lost when doing so
-Energy or Chakra must be conserved to accomplish difficult ninjitsus
-Energy constantly moves toward a form of disorder
-Conserve Energy or the world will end
-Energy is never created or destroyed, it just changes forms.

Answers

Answer:

I say the last option

Explanation:

I hope this help let me know if you have any questions

Carboxylic acid derivatives undergo hydrolysis to make carboxylic acids.

a. True
b. False

Answers

Answer:

TRUE

Explanation:

All carboxylic acid derivatives have in common the fact that they undergo hydrolysis (a cleav- age reaction with water) to yield carboxylic acids. with hydroxide ion to yield a carboxylate salt and an alcohol. The carboxylic acid itself is formed when a strong acid is subsequently added to the reaction mixture.

PLS MARK BRAINLIEST

True

All carboxylic acid derivatives have in common the fact that they undergo hydrolysis (a cleav- age reaction with water) to yield carboxylic acids. with hydroxide ion to yield a carboxylate salt and an alcohol. The carboxylic acid itself is formed when a strong acid is subsequently added to the reaction mixture.
PLS MARK BRAINLY PLSSSSSSS

A eudiometer is used to collect hydrogen gas in a chemical reaction, as in your Exp 7. The volume of the gas in the tube (when pressure is held
constant) is 479.10 mL. The pressure of the atmosphere during the experiment is 758.3 mmgHg, and the temperature of the water and gas is
19.0*C. The water vapor pressure at this temperature is 16.5 torr.
Calculate the mass of hydrogen, in mg, collected.

Answers

Answer:

39.29 mg

Explanation:

Step 1: Calculate the partial pressure of hydrogen

The pressure of the atmosphere is equal to the sum of the partial pressures of the water and the hydrogen. (1 Torr = 1 mmHg)

P = pH₂O + pH₂

pH₂ = P - pH₂O = 758.3 mmHg - 16.5 mmHg = 741.8 mmHg

We will convert it using the conversion factor 1 atm = 760.0 mmHg.

741.8 mmHg × 1 atm/760.0 mmHg = 0.9761 atm

Step 2: Convert 19.0 °C to Kelvin

We will use the following expression.

K = °C + 273.15 = 19.0 + 273.15 = 292.2 K

Step 3: Calculate the mass of hydrogen

First, we will calculate the moles of hydrogen using the ideal gas equation.

P × V = n × R × T

n = P × V / R × T

n = 0.9761 atm × 0.47910 L / (0.08206 atm.L/mol.K) × 292.2 K = 0.01950 mol

The molar mass of hydrogen is 2.015 g/mol. The mass of hydrogen is:

0.01950 mol × 2.015 g/mol = 0.03929 g = 39.29 mg

How many moles of HNO3 are needed to prepare 5.7 liters of a 1.64 M solution of HNO3

Answers

We are given:

Volume of Solution: 5.7 Liters

Concentration: 1.64 Molar

Number of moles required:

We know that the formula for concentration (in molar) is:

M = N / V              

where M is the concentration, N is the number of moles, and V is the volume of solution (in L)

plugging the given values in the equation:

1.64 = N / 5.7

N = 1.64 * 5.7            

N = 9.35 moles

A sample of gas occupies 10.0 L at 240°C under a pressure of
80.0 kPa. At what temperature would the gas occupy 20.0 L if
we increased the pressure to 107 kPa?

Answers

Answer: 1090°C

Explanation: According to combined gas laws

(P1 × V1) ÷ T1 = (P2 × V2) ÷ T2

where P1 = initial pressure of gas = 80.0 kPa

V1 = initial volume of gas = 10.0 L

T1 = initial temperature of gas = 240 °C = (240 + 273) K = 513 K

P2 = final pressure of gas = 107 kPa

V2 = final volume of gas = 20.0 L

T2 = final temperature of gas

Substituting the values,

(80.0 kPa × 10.0 L) ÷ (513 K) = (107 kPa × 20.0 L) ÷ T2

T2 = 513 K × (107 kPa ÷80.0 kPa) × (20.0 L ÷ 10.0 L)

T2 = 513 K × (1.3375) × (2)

T2 = 1372.275 K

T2 = (1372.275 - 273) °C

T2 = 1099 °C

1090 degree Celsius

hope it helps

A sample of nitrogen gas occupies 117 mL at 100°C. At what
temperature would it occupy 234 mL if the pressure does not
change? (express answer in K and °C)
47
Page
8 I 8
- Q +

Answers

Answer:

The new temperature of the gas is 746 K.

Explanation:

Given that,

The volume of the gas, V₁ = 117 mL

Temperature, T₁ = 100°C = 373

Final volume of the gas, V₂ = 234 mL

We need to find the final temperature. The relation between temperature and volume is given by :

[tex]\dfrac{V_1}{V_2}=\dfrac{T_1}{T_2}\\\\T_2=\dfrac{T_1V_2}{V_1}\\\\T_2=\dfrac{373\times 234}{117}\\\\T_2=746\ K[/tex]

So, the new temperature of the gas is 746 K.

g Identify the process in which the entropy increases. Group of answer choices a decrease in the number of moles of a gas during a chemical reaction the phase transition from a gas to a liquid the phase transition from a solid to a gas freezing water

Answers

Answer:

phase transition from a solid to a gas

Explanation:

Entropy refers to the degree of disorderliness in a system. The more disorderly a system is, the greater the entropy of the system.

Decrease in the number of moles of a gas decreases the entropy of the system. Similarly, the entropy of solids is less than that of liquids. The entropy of liquids is less than that of gases.

Therefore, a change of phase from solid to gas represents an increase in entropy of the system.


Which redox reaction would most likely occur if zinc and copper metal were
added to a solution that contained zinc and copper ions?
Click for a reduction potential chart
A. Cu + Zn → Cu2+ + Zn2+
B. Cu + Zn2+
Cu2+ + Zn
C. Cu2+ + Zn → Cu + Zn2+
D. Cu2+ + Zn2+ → Cu + Zn

Answers

Answer:

C

Explanation:

b/c when copper and zinc metal are addedto solution,then the solution will be consider under redox reaction

[tex]Cu^{2+} + Zn[/tex] → [tex]Cu + Zn^{2+}[/tex] is the redox reaction. Hence, option C is correct.

What is Redox Reaction?

A chemical reaction taking place between an oxidizing substance and a reducing substance.

The oxidizing substance is used to lose electrons in the reaction, and the reducing substance is used to gain electrons.

On the reduction potential chart, zinc is a stronger oxidizing agent than, Copper (Cu), which is a reducing agent as compared to silver

The redox reaction most likely occurs if silver and copper metal were added to a solution that contained silver and copper ions is ;

[tex]Cu^{2+} + Zn[/tex] → [tex]Cu + Zn^{2+}[/tex]

Learn more about Redox Reaction here ;

brainly.com/question/13293425

#SPJ5

Bond length is the distance between the centers of two bonded atoms. On the potential energy curve, the bond length is the internuclear distance between the two atoms when the potential energy of the system reaches its lowest value. Given that the atomic radii of H and Br are 37.0 pm and 115 pm , respectively, predict the upper limit of the bond length of the HBr molecule. Express your answer to three significant figures and include the appropriate units. View Available Hint(s)for Part C

Answers

Answer:

The answer is "152 pm".

Explanation:

The bond length from the values inside the atomic radii is calculated according to the query. This would be the upper limit of a molecule's binding length.

The atomic radius of [tex]H= 37.0 \ pm[/tex]

The atomic radius of [tex]Br = 115.0 \ pm[/tex]

[tex]\text{Bond length = Atomic radius of H + Atomic radius of Br}[/tex]

                    [tex]= 37.0\ pm + 115.0 \ pm\\\\= 152\ pm[/tex]

State the different radiations emitted by radioactive elements.

Answers

The emissions of the most common forms of spontaneous radioactive decay are the alpha (α) particle, the beta (β) particle, the gamma (γ) ray, and the neutrino.

Answer: Alpha, beta, and gamma after the first three letters of the Greek alphabet. Alpha and beta particles consist of matter, and gamma rays are bursts of energy. The type of radiation emitted depends on the radioactive substance; cesium-137, for example, produces beta and gamma radiation but not alpha particles.

A substance that donates a pair of electrons to form coordinate covalent bond is called

Answers

Lewis base: any species that can donate a pair of electrons and form a coordinate covalent bond. ligand: molecule or ion that surrounds a transition metal and forms a complex ion; ligands act as Lewis bases

The enthalpy of formation for CO2 (s) and CO2 (g) is: -427.4 KJ/mole and -393.5 KJ/mole, respectively. The sublimation of dry ice is described by CO2 (s) → CO2 (g).

The enthalpy needed to sublime 986 grams of CO2 is:
(a) 181.5 Kcal
(b) 611.7 Kcal
(c) 248.3 Kcal
(d) 146.2 Kcal

Answers

Answer:

a. 181.5 kcal

Explanation:

Step 1: Calculate the enthalpy of the process (ΔH°).

Let's consider the following process.

CO₂(s) → CO₂(g)

We can calculate the enthalpy of the process using the following expression.

ΔH° = ∑ np × ΔH°f(p) - ∑ nr × ΔH°f(r)

ΔH° = 1 mol × ΔH°f(CO₂(g)) - 1 mol × ΔH°f(CO₂(s))

ΔH° = 1 mol × (-393.5 kJ/mol) - 1 mol × (-427.4 kJ/mol) = 33.9 kJ

According to the balanced equation, 33.9 kJ are required to sublime 1 mole of CO₂.

Step 2: Convert 986 g of CO₂ to moles

The molar mass of CO₂ is 44.01 g/mol.

986 g × 1 mol/44.01 g = 22.4 mol

Step 3: Calculate the enthalpy needed to sublime 22.4 moles of CO₂

22.4 mol × 33.9 kJ/1 mol = 759 kJ

We can convert it to Kcal using the conversion factor 1 kcal = 4.184 kJ.

759 kJ × 1 kcal/4.184 kJ = 181.5 kcal

what is the charge on the Mn ions in Mn2o3? 1+, 2+, 3+,3-,4+?

Answers

hey here’s your answer hope this helps you!!!!

Two flasks are connected by a closed valve. One contains gas particles and the other contains a vacuum. If the valve is opened such that the particles move until they fill both flasks, the process by which the particles can reconvene entirely in one of the flasks is:

Answers

Answer: The process by which the particles can reconvene entirely in one of the flasks is: NONSPONTANEOUS.

Explanation:

The spontaneity of a process can affect the distribution of energy and matter within the system. Different chemical or physical processes have the natural tendency to occur in one direction under a given set of conditions. For example:

--> when water is pour down a hill it naturally flows down but it requires outside energy maybe from a water pump to flow up the hill and ,

--> during an iron rust, iron that is exposed to atmosphere will corrode, but rust is not converted to iron without intentional chemical treatment.

Therefore, a spontaneous process is one that occurs naturally under certain conditions. While a NONSPONTANEOUS process, on the other hand, will not take place unless it is initiated by the continual input of energy from an outside source. A process that is spontaneous in one direction under a particular set of conditions is nonspontaneous in the REVERSE direction.

From the two flasks that where connected through a valve, once the valve was opened, the gas spontaneously becomes evenly distributed between the flasks. To reverse this, it would require an external energy making the reconvening of the particles back to the first flask a NONSPONTANEOUS PROCESS .

In nature, one common strategy to make thermodynamically unfavorable reactions proceed is to couple them chemically to reactions that are thermodynamically favorable. As long as the overall reaction is thermodynamically favorable, even the unfavorable reaction will proceed.
Part A
Consider these hypothetical chemical reactions:
A⇌B,ΔG= 14.8 kJ/mol
B⇌C,ΔG= -29.7 kJ/mol
C⇌D,ΔG= 8.10 kJ/mol
What is the free energy, ΔG, for the overall reaction, A⇌D?
Part B
Firefly luciferase is the enzyme that allows fireflies to illuminate their abdomens. Because this light generation is an ATP-requiring reaction, firefly luciferase can be used to test for the presence of ATP. In this way, luciferase can test for the presence of life. The coupled reactions are
luciferin+O2ATP⇌⇌oxyluciferin+lightAMP+PPi
If the overall ΔG of the coupled reaction is -7.50 kJ/mol , what is the equilibrium constant, K, of the first reactions at 11 ∘C ? The ΔG for the hydrolysis of ATP to AMP is −31.6 kJ/mol.

Answers

Answer:

[tex]\triangle G= -6.7 KJ/mol[/tex]

Explanation:

From the question we are told that:

Chemical Reactions:

X=A⇌B,ΔG= 14.8 kJ/mol

Y=B⇌C,ΔG= -29.7 kJ/mol

Z=C⇌D,ΔG= 8.10 kJ/mol

Since

Hess Law

The law states that the total enthalpy change during the complete course of a chemical reaction is independent of the number of steps taken.

Therefore

Generally the equation for the Reaction is mathematically given by

[tex]T = +1 * X +1 * Y +1 *Z[/tex]

Therefore the free energy, ΔG is

[tex]\triangle G=1 * \triangle G*X +1 * \triangle G*Y +1 * \triangle G *Z[/tex]

[tex]\triangle G= +1 * (14.9) +1 * (-29.7) +1 * (8.10)[/tex]

[tex]\triangle G= -6.7 KJ/mol[/tex]

Which shampoo would be displayed third?

Answers

Answer:

Biolage is the answer

Explanation:

Because it's price is third most

How many grams of H₂SO₄ are contained in 2.00 L of 6.0 M H₂SO₄?

Please explain and show work.

Answers

Answer:

1176 grams

Explanation:

nH2SO4 =2*6=12 mol

mH2SO4=12*98=1176 grams

Answer:

solution given:

molarity of H₂SO₄=6 M

volume=2L

no of mole =6M*2=12mole

we have

mass =mole* actual mass=12*98=1176g

the mass is 1176g.

Rank the compounds NH3, CH4, and PH3 in order of decreasing boiling point. Choices: A) NH3 > CH4 > PH3 B) CH4 > NH3 > PH3 C) NH3 > PH3 > CH4 D) CH4 > PH3 > NH3 E) PH3 > NH3 > CH4

Answers

Answer:

C) NH3 > PH3 > CH4

Explanation:

The boiling point of a substance depends on the nature of intermolecular interaction between the molecules of the substance. The greater the magnitude of intermolecular interaction between the molecules of the substance, the higher the boiling point of the substance.

Both NH3 and PH3 have intermolecular hydrogen bonding between their molecules. However, since nitrogen is more electronegative than phosphorus, the magnitude of intermolecular hydrogen bonding in NH3 is greater than in PH3 hence NH3 has a higher boiling point than PH3.

CH4 molecules only have weak dispersion forces between them hence they exhibit the lowest boiling point.

Diisopropyl ether reacts with concentrated aqueous HI to form two initial organic products

a. True
b. Fasle

Answers

Answer:

True

Explanation:

The reaction between Diisopropyl ether and concentrated aqueous HI forms two initial organic products as shown in the image attached.

The hydrogen of the HI becomes attached to the oxygen in the ether leading to a cleavage of the C-O bond to yield the first compound. The I^- become attached to the other moiety in the original molecule to yield the second compound as shown in the image attached.

(URGENT FOR BRAINLIEST!!)
The diagram below shows the movement of Earth plates.

The picture shows two Earth plates one beside the other. The plate on the left is shown moving towards the right and the plate

Which of these features is most likely formed as a result of the movement of Earth plates shown in the diagram? (2 points)


a canyon

a fault

a mountain

a ridge

Answers

Answer:

mountain

Explanation:

when plates move towards each other they create mountains

All of the following statements concerning real cases is correct EXCEPT Group of answer choices molecules of real gases are attracted to each other. molecules of real gases occupy no volume. nonideal gas behavior is described by the Van der Waals Equation. the pressure of a real gas is due to collisions with the container. the pressure of a real gas at low temperatures is lower than for ideal gases.

Answers

Answer:

molecules of real gases occupy no volume.

Explanation:

As all the real gases are composed of particles that occupy the non-zero volume that is the excluded volume. If the gas is behaving in an ideal manner. The correction becomes negatable and is relative to the total volume. The extended volume is volume that is taken by the non ideal gas particles.

How many grams are of aluminum nitrate are contained in 0.150 moles of Al(NO3)3? ​

Answers

Answer:

31.95 g

Explanation:

find the molar mass of Al(NO3)3

(Al = 27, N = 14, O = 16)

molar mass of Al(NO3)3 = 27+ (14+16×3)×3

= 213 gmol^-

mass = 213 ×0.15

= 31.95g

An important difference between fuel cells and batteries is that batteries _______. Select the correct answer below: do not require a continuous source of fuel require a continuous source of fuel are able to expel products are constantly resupplied with reactants

Answers

Answer: the correct option is that batteries (do NOT require a continuous source of fuel).

Explanation:

A battery can be classified as an electrochemical cell that has the ability to produce electric current. They do NOT require a continuous supply of fuel because it contains all the reactants needed to produce electricity. Below are some examples of batteries that are commonly used:

--> Primary battery: This is a single use battery because it can't be recharged. A typical example is the dry cell.

--> Secondary battery: This type of battery can be recharged. They are used as a power source for smartphones, electronic tablets, and automobiles.

A FUEL CELL is known as a device that converts chemical energy into electrical energy. Fuel cells are similar to batteries but require a continuous source of fuel, often hydrogen. They will continue to produce electricity as long as they are constantly resupplied with reactants. Hydrogen fuel cells have been used to supply power for satellites, space capsules, automobiles, boats, and submarines.

Answer:

accumulate reaction byproducts

Explanation:

Batteries accumulate reaction byproducts.  Fuel cells are similar to batteries but require a continuous source of fuel, often hydrogen. They will continue to produce electricity as long as fuel is available. Hydrogen fuel cells have been used to supply power for satellites, space capsules, automobiles, boats, and submarines.  A battery is an electrochemical cell or series of cells that produces an electric current.

All of the following statements concerning crystal field theory are true EXCEPT Group of answer choices in an isolated atom or ion, the five d orbitals have identical energy. low-spin complexes contain the maximum number of unpaired electrons. in low-spin complexes, electrons are concentrated in the dxy, dyz, and dxz orbitals. the energy difference between d orbitals often corresponds to an energy of visible light. the crystal field splitting is larger in low-spin complexes than high-spin complexes.

Answers

Answer:

low-spin complexes contain the maximum number of unpaired electrons.

Explanation:

In the crystal field theory, the magnitude of crystal field splitting and the pairing energy determines whether a complex will be low spin or high spin.

Low spin complexes often have greater magnitude of crystal field splitting energy than low spin complexes.

High spin complexes have maximum number of unpaired electrons(most of the electrons are unpaired) while low spin complexes have a minimum number of unpaired electrons in a complex(most of the electrons are paired).

How are radioactive isotopes used to diagnose thyroid problems?
Answers

A.
Production of radioactive iodine by the thyroid is measured.

B.
Uptake of radioactive iodine by the thyroid gland is measured.

C.
Destruction of damaged cells by radioisotopes is measured.

D.
Absorption of gamma rays from ingested radioisotopes is measured.
Question

Answers

Answer:

A

Explanation:

uptakw of raduoactive iofine by the thyroid gland js measurd


Write the symbol for every chemical element that has atomic number greater than 55 and less than 140.8 u

Answers

Answer on the picture

Which of the following is most likely to happen when a sound wave reflects
off a hard surface? (Assume that neither the source of the sound nor the hard
surface is moving.)
A. A change in speed
B. An echo
C. A change in pitch
D. A beat frequency

Answers

В

an echo is caused by the fact that waves can be reflected by solid surfaces, this is due to the dynamic pattern of rarefactions and air seals near the reflecting surface

Other Questions
about ritual of tharu caste Find y' for the following. identify three ethical, legal, or social issues raised by biotechnology. Which is the only element in group 1 on the periodic table that forms covalent bonds?hydrogenlithiumpotassiumsodium. You decide to determine, once and for all, which chocolate brownies are best-- yours or your sister-in-law's Yolanda-- by devising a test of hypothesis. She is a superb baker and she mocks your baking as inferior. Undaunted, you decide to randomly select 100 names from the NYC phone book. You contact each selected individual and they agree to participate in your study. Then, you send your brownies with instructions for rating the taste and one week later you send Yolanda's brownies with the same instructions. Each group rates the brownies on a 10 point ordinal scale--10 implies exquisite and 1 implies inedible. True or False: This test is performed on paired or matched samples. BRAINLEST IF CORRECT Choose the correct form of the past tenses Last night at 9 p.m.I (be) at home. I ( watch) television when suddenly I (hear) a noise. I went to check and it ( turn out) that someone ( break) a window at the back of the house! I (try) to phone the police, but the burglar (cut) the phone line so I couldn't get through. I (run) upstairs and I (phone) the police on my mobile. The burglar heard me and while I (speak) he ran away. It was a frightening experience. Hey, babes! Here is a question for today-How do you write an equation to show the relationship between the Independent and Dependent Variables? Someone please help me. Asap ? Help!!!! Many people volunteer their time to help others, either through non-profit organizations, churches, or other charitable venues. Write an essay convincing readers to find a charity and volunteer their time. (3 to 5 paragraphs please) express 572 in simplest radical form. Which factor played the most important role in the rise of totalitarianism inItaly during the 20th century?O A. The rapid growth of Jewish populations in Italian citiesB. The damage World War I had done to Italy's economyC. The declining popularity of nationalism and militarism in ItalyO D. The replacement of the Italian monarchy with elected leadership In the small country of Economerica, there are 6 thousand people employed, 1 thousand people unemployed, and 3 thousand people of working age not included in the labor force. One thousand students graduate from the university and seek jobs in the country, but not one graduate is able to find one. Half of the new graduates believe there is no chance of finding a job and return home to live with their parents. Ceteris Paribus, what would the new unemployment rate be in Economerica?A. 14.29%B. 20.00%C. 25.00%D. 45.45% 15. On Sports Day, Mike runs 100 metres in 13.89 seconds and Neal runs the same distance in 13.01 seconds. Who is the FASTER runner? Give me 10 semtences,explainwhy it is important for you to vote this coming 2022 presidential election. 1. What outfits (male) rich/fancy people wear other then suits and tophats? 2. I remember seeing a fancy character in a movie wearing this thing on his neck/collar of shirt thats like a napkin but it was small(ish) and (probably) not a napkinI have a character who is the rich and fancy type but I already have characters with suits and tophats so I want to be more original instead of copying and pasting suits onto each of my characterEDIT: OHHHH the "napkin" is actually called a jabot, no need to answer the 2ne question now Does the estimate of a tolerance level of 68.26% of all patient waiting times provide evidence that at least two-thirds of all patients will have to wait less than 8 minutes? What does point H represent? In an annual report to investors, an investment firm claims that the share price of one of their bond funds had very little variability. The report shows the average price as $15.00 with a variance of 0.19. One of the investors wants to investigate this claim. He takes a random sample of the share prices for 22 days throughout the last year and finds that the standard deviation of the share price is 0.2517. Can the investor conclude that the variance of the share price of the bond fund is different than claimed at = 0.05. Assume the population is normally distributed.Required:State the null and alternative hypotheses. Round to four decimal places when necessary What is the GCF of the expression 7xyz - 21xyz + 49yz + 14yz2?