1. Convert each of the following into scientific notation.

Answer:

the answer is A

Answer: Copper

Explanation: did it on Edgenuity 2020

Answer:

first is copper

second is gold

Answer:

Methyl Alcohol.

Acetate

Heptane

Dioxane

Explanation:

The boiling point of liquids are measure by observing the gas pressure or vapors temperature. There are few liquids whose boiling point is difficult to measure. The gas pressure differs for every liquid. It is important to observe the vapor pressure also to identify the boiling point. The most difficult boiling point identification is for Methyl alcohol as it has ability to absorb different level of pressure.

The liquids are Methyl Alcohol, Acetate, Heptane,Dioxane

Information regarding the liquids:

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Answer:

The two objects have different volumes.

Explanation:

The density of an object measures how closely packed the mass in the object is. Density of an object is obtained by taking the ratio of the mass of an object and its volume.

Density = mass/volume

The mass present in an object is constant, but the volume may vary with temperature. The volume of substances generally increases with temperature, therefore, density decreases with increase in volume.

Two objects at the same temperature having equal masses may or may not have the same density depending on the volume each object occupy.

If two substances are at the same temperature and have equal masses but different densities, then they must have different volumes.

Answer:

I believe it's because density is how dense something is. So even if the volume(how much space it takes up in an object) is greater, if the densitity of the object is greater then the density of the water it will sink.

Explanation:

Answer:

Explanation:

Growing Peas

Planting depth should be roughly 2 inches with a spacing of about 2 inches apart. Water well at planting and provide at least 1 inch of water per week, particularly during the flowering and pod production stages. As the temperature rises, the vines may need to be deeply watered almost every day.

Make sure to moniter it and change the water depending on how dry or overwatered it looks like. :)

Answer:

1600

Explanation:

5×10^4÷2.5×10^2

(5×10^4)

(10^4)

(5×40)

(200)

(200÷2.5)

(80)

(80×10^2)

(10^2)

(20)

(80×20)

Answer is 1600.

Sorry if it's not correct.

Answer:

The solution is not ideal and shows a positive deviation from Raoult’s law since Psolution (experimental) > Psolution (actual).

Explanation:

Number of moles of CS2 = 3.95g/76.13gmol-1 = 0.0519 moles

Number of moles of acetone = 2.43g/58.08gmol-1 = 0.0418 moles

Total number of moles = 0.0937 moles

Mole fraction of CS2 = 0.0519/0.0937 = 0.5538

Mole fraction of acetone = 0.0418/0.0937 = 0.4461

From Raoult’s law;

PCS2 = 0.5538 × 515 torr = 285.207 torr

Pacetone = 0.4461 × 332 torr = 148.1052 torr

Total pressure = 285.207 torr + 148.1052 torr = 433.3 torr

Answer:

Atom is the smallest particle of pure sustance which can take part in a chemical reaction.A chrged atom is called an ion.

A molecule of an element or compound is the smallest particle of it that is stable and capable of independent existence. The molecules of element and compound are different.

Answer:

Strong acids are 100% ionized in water.

Explanation:

A strong acid is any acid that is completely ionized in water (achieves 100% ionization). Weak acids do not ionize completely in water. Many weak acids ionize to a very small extent in pure water.

Examples of strong acids are HCl, H2SO4, HNO3, etc.

Answer:

25.0%

A solution of benzene (C6H6) and toluene (C7H8) is 25.0% benzene by mass. At 25 °C the vapor pressures of pure benzene and pure toluene are 94.2 torr and 28.4 torr, respectively.

All living organisms are composed of one or more cells. The cell is the basic unit of structure and organization in organisms. Cells arise from pre-existing cells.

Answer:

There will be 3 peaks.

Relative height of the atomic peaks would be; 158, 160 and 162

Explanation:

We are told that Bromine has two isotopes namely 79Br and 81Br in a 1 : 1 ratio (50 : 50).

This means that a compound which contains 1 bromine atom will have two peaks in the molecular ion region but it depends on which bromine isotope is contained in the molecular ion.

Thus;

Relative height of atomic peaks is given by;

m/z = 79Br¯ 79Br+ = 158

79Br¯ 81Br+ = 160

81Br¯ 81Br+ = 162

Answer:

A- conjugate acid

B- conjugate base

C- conjugate base

D- conjugate acid

Explanation:

According to the Brownstead-Lowry definition of acids, an acid donates a proton while a base accepts the proton.

If we look at the species ABCD, species A and D donate protons while species B and C accept protons.

C is the conjugate base of A while D is the conjugate acid of B, hence the answer.

The three main lines of evidence for revolution is Darwin used multiple lines of evidence to support his theory of evolution by natural selection -- fossil evidence, biogeographical evidence, and anatomical evidence.

The three main lines of evidence for evolution is fossil evidence, biogeographical evidence and anatomical evidence.

In biology evolution is a process in which change in the characterisitics of any species over a several generation on the basis of natural selection method.

The three main lines of evidence for evolution are:

So, three lines of evidences are fossil evidence, biogeographical evidence and anatomical evidence.

To know more about evolution, visit the below link:
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Answer:

A-210, n-125

A-207, n-122

A-209, n-124

Explanation:

The mass number is the sum of the number of protons and neutrons in the nucleus of an atom.

Astatine has an atomic number of 85, this is the number of protons in its nucleus. We must subtract the given number of neutrons in each option from the mass number and consider the difference. If the difference between the mass number and number of neutrons is exactly 85, then that option represents one of the isotopes of astatine.

Answer:

9.744g of monosodium succinate.

4.925g of disodium succinate.

Explanation:

To find pH of the buffer produced by the mixture of monosodium succinate-Disodium succinate is obtained from H-H equation:

pH = pKa + log ([Na₂Suc] / [NaHSuc])

As you want a pH of 5.28 and pKa is 5.64:

5.28 = 5.64 + log ([Na₂Suc] / [NaHSuc])

-0.36 = log ([Na₂Suc] / [NaHSuc])

0.4365 = ([Na₂Suc] / [NaHSuc]) (1)

As total concentration of the buffer is 100mM = 0.100M:

0.100M = [Na₂Suc] + [NaHSuc] (2)

Replacing (2) in (1):

0.4365 = (0.100M - [NaHSuc] / [NaHSuc])

0.4365 = (0.100M - [NaHSuc] / [NaHSuc])

0.4365 [NaHSuc] = 0.100M - [NaHSuc]

1.4365 [NaHSuc] = 0.100M

[NaHSuc] = 0.0696M

And:

[Na₂Suc] = 0.0304M

As volume of the buffer is 1L:

[NaHSuc] = 0.0696 moles

[Na₂Suc] = 0.0304 moles

Using molar mass of both substances:

Mass of monosodium succinate:

0.0696moles * (140g / 1mol) = 9.744g of monosodium succinate.

Mass of disodium succinate:

0.0304moles * (162g / 1mol) = 4.925g of disodium succinate.

Answer:

non polar and neutral polar and neutral acidic and polar basic and polar

Answer:

H₃O⁺.

Explanation:

Hello,

In this case, ionization of ethanol yields hydrogen cations and ethoxide anions as follows:

[tex]CH_3COOH+H_2O\rightleftharpoons H_3O^++CH_3COO^-[/tex]

Which is at equilibrium as ethanol is a weak acid. Thus, since the conjugate acid is formed by the outgoing H⁺ and the water, we say that the conjugate acid is then the hydroxonium ion, H₃O⁺ whereas the conjugate base is the remaining anion CH₃COO⁻.

Best regards.

Answer:

B

Explanation:

Sea level changes due to many different  geological events  and can rise or fall over time .

Sea level changes due to global warming , the water being added to the seas as the glaciers melts due to global warming and the expansion of water when it warms.

The sea level also increases due to land processes like soil erosion ,oil and ground water pumping.Changes in land water storage like dams ,changes in global precipitation patterns also make a significant contribution  to change in sea level.

The increased emission of green house gases is a dominant cause  for change in sea level.Fifty percent of sea level rise is due to thermal expansion of seas and the rest is due to the geological activities.

Learn more about  global warming here:

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#SPJ2

Hello. This question is incomplete. The full question is:

A chemist must prepare 500.0mL of hydrobromic acid solution with a pH of 0.50 at 25°C. He will do this in three steps: Fill a 500.0mL volumetric flask about halfway with distilled water. Measure out a small volume of concentrated (5.0M) stock hydrobromic acid solution and add it to the flask. Fill the flask to the mark with distilled water. Calculate the volume of concentrated hydrobromic acid that the chemist must measure out in the second step. Round your answer to significant digits.

Answer:

31.62 mL

Explanation:

To achieve this result, you must start by calculating the H + concentration. You will do this using the following formula:

pH = -log [H +]

0.50 = -log [H +]

[H +] = 10 ^ -0.50

[H +] = 0.31623 mol / L

After that you must consider that hydrobromic acid will have a weak capacity to disassociate, since it has a strong nature. In this case, we can consider that [HBr] = [H +] = 0.31623 mol / L.

After reaching this reason, it is necessary that you dilute the stock solution, using the formula:

C1V1 = C2V2

5.0 * V1 = 0.31623 * 500.0

V1 = 31.62 mL

And so you finish the answer.

Answer:

analyze

Explanation:

After testing is analyzing your data then you compare your data to your hypothesis to see if they match  

Answer:

a) pH = 9.44

b) 25mL of HBr are required.

c) pH = 5.37

d) pH = 9.26

Explanation:

The equilibrium of NH₃ in water occurs as follows:

NH₃(aq) + H₂O(l) ⇄ NH₄⁺(aq) + OH⁻(aq)

Kb = 1.8x10⁻⁵ = [NH₄⁺] [OH⁻] / [NH₃]

The reaction of NH₃ with HBr is:

NH₃ + HBr ⇄ NH₄⁺ + Br⁻

That means when you add X moles of HBr before to reach the equivalence point, the moles are:

Moles NH₃ = Initial moles - moles HBr

Moles NH₄⁺ = Moles HBr

Initial moles NH₃ = 0.050L * (0.05mol / L) = 2.5x10⁻³ moles NH₃

Moles HBr = 0.010L * (0.10mol / L) = 1x10⁻³ moles HBr

Thus, after the reaction:

Moles NH₃ = 1.5x10⁻³moles

Moles NH₄⁺ = 1x10⁻³ moles

Using Henderson-Hasselbalch equation, pH of this solution is:

pOH = pKb + log [NH₄⁺] / [NH₃]

Where pKb is -log Kb = 4.74

And [] could be taken as moles of each compound:

pOH = 4.74 + log [1x10⁻³ moles] / [1.5x10⁻³ moles]

pOH = 4.56

And pH = 14 - 4.56

b) To reach equivalence point, we need to add 2.5x10⁻³ moles HBr:

2.5x10⁻³ moles HBr * (1L / 0.10mol) = 0.025L = 25mL of HBr are required

c)At equivalence point, you will have just 2.5x10⁻³ moles of NH₄⁺ in 50.0mL + 25mL = 75mL. The molar mass of NH₄⁺ is:

[NH₄⁺] = 2.5x10⁻³mol / 0.075L = 0.0333M

The equilibrium of NH₄⁺ is:

NH₄⁺ ⇄ NH₃ + H⁺

Ka = [NH₃] [H⁺] / [NH₄⁺] = 5.556x10⁻¹⁰

[NH₃] = [H⁺] because both comes from the same equilibrium and [NH₄⁺] = 0.0333M:

[X] [X] / [0.0333M] = 5.556x10⁻¹⁰

[X]² = 1.85x10⁻¹¹M

[X] = [H⁺] = 4.3x10⁻¹¹M

pH = -log [H⁺] = 5.37

d) At midpoint, [NH₃] = [NH₄⁺]. Using H-H equation:

pOH = 4.74 + log [NH₃] / [NH₄⁺]

pOH = 4.74

And pH = 14 - 4.74

Answer:

It takes 1,068.76 grams of nitrogen to fill an 855 L tank at STP.

Explanation:

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C or 273.15 °K are used and are reference values for gases.

On the other side, the pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:  

P*V = n*R*T

where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas.

So, in this case:

Replacing:

1 atm* 855 L= n* 0.082 [tex]\frac{atm*L}{mol*K}[/tex] * 273.15 K

Solving:

[tex]n=\frac{1 atm* 855 L}{0.082\frac{atm*L}{mol*K} *273.15 K }[/tex]

n= 38.17 moles

Being the molar mass of nitrogen N2 equal to 28 g / mol, you can apply the following rule of three: if there are 28 grams in 1 mole, how much mass is there in 38.17 moles?

[tex]mass=\frac{38.17 moles*28 grams}{1 mole}[/tex]

mass= 1,068.76 grams

It takes 1,068.76 grams of nitrogen to fill an 855 L tank at STP.

Answer:

Explanation:

There is no way to measure the absolute value of the enthalpy of a substance. Only values relative to an arbitrary reference can be determined.

The reference point for all enthalpy expressions is called the standard enthalpy of formation (ΔHºf). Substances are said to be in the standard state at 1 atm, hence the term “standard enthalpy.” The superscript “°” represents standard-state conditions (1 atm), and the subscript “f” stands for formation. By convention, the standard enthalpy of formation of any element in its most stable form is zero.

For instance, molecular oxygen (O₂) is more stable than the other allotropic form of oxygen, ozone (O₃), at 1 atm and 25°C. Thus, we can write ΔHºf (O₂) 5 0, but ΔHºf (O₃) 5 142.2 kJ/mol.

Based on this reference for elements, we can define the standard enthalpy of formation of a compound as the heat change that results when 1 mole of the compound is formed from its elements at a pressure of 1 atm.

Answer:

This is the enthalpy change that occurs when a compound is formed from its component elements.

Explanation:

This is the enthalpy change that occurs when a compound is formed from its component elements.

Answer:

287.6g CHCl₃

Explanation:

We can determine the structure of Chloroform, dividing the mass of each element in its molar mass:

C = 12.0g * (1mol /12g) = 1 mol C

H = 1.01g * (1mol / 1.01g) = 1 mol H

Cl = 106.4g * (1mol / 35.45g) = 3 moles Cl

The structure is CHCl₃. And its molar mass is: 12.0g C +1.01g H + 106.4g Cl = 119.41g/mol

Now, the moles of carbon in the second sample = Moles of chloroform are:

28.9g C * (1mol / 12g) = 2.408 moles C = Moles CHCl₃

And its mass is:

2.408 moles CHCl₃ * (119.41g/mol) =

Answer: An atom is the sub-component of a molecule, or the smallest unit of matter. It is the smallest part an element can divide into. A molecule is made up of atoms that are bound by ionic, covalent or metallic bond.

Answer:

veryy help ful

Explanation:

An atom is the sub-component of a molecule, or the smallest unit of matter. It is the smallest part an element can divide into. A molecule is made up of atoms that are bound by ionic, covalent or metallic bond.

Answer:

The answer to your question is given below.

Explanation:

Sodium (Na) is a group 1 element because it has 1 electron in it's outermost shell.

Sodium ion (Na+) is formed when sodium atom (Na) lose it's outermost electron to attain the octet configuration of the noble gas element.

This can further be seen from the equation given below:

Na —> Na+ + e

Thus, we can represent the above in electronic configuration form as follow:

Na (11) => 1s² 2s²2p⁶ 3s¹

Na+ (10) => 1s² 2s²2p⁶