4. If 175 undecayed nuclei remain from a sample of 2800 nuclei, how many half-
lives have passed? (Show your work.) *
Your answer

Answers

Answer 1

Answer:

X = 4

Explanation:

Start 2800

End 175

175 = 2800x(0.5)^X

175/2800 = 0.5^X

0.0625 = 0.5^X

log(0.5 x) = log(0.0625)

x · log(0.5) = log(0.0625)

-0.301x = -1.204

x = -1.204/-0.301

x = 4


Related Questions

I’ve gotten the answer as x=.478 but when plugging back in, .46/.478 ≠ .22. Help please

Answers

Answer:

15. 2.66 moles .

16. 2.09L.

Explanation:

Molarity of a solution is simply defined as the mole of solute per unit litre of the solvent. Mathematically, it is represented as:

Molarity = mole /Volume.

With the above formula, let us answer the questions given above

15. Data obtained from the question include the following:

Volume of solution = 1.4L

Molarity = 1.9M

Mole of solute =.?

Molarity = mole /Volume

1.9 = mole / 1.4

Cross multiply

Mole = 1.9 x 1.4

Mole = 2.66 moles

Therefore, the mole of the solute present in the solution is 2.66 moles.

16. Data obtained from the question include the following:

Mole of solute = 0.46 mole

Molarity = 0.22M

Volume of solvent (water) =.?

Molarity = mole /Volume

0.22 = 0.46/Volume

Cross multiply

0.22 x Volume = 0.46

Divide both side 0.22

Volume = 0.46/0.22

Volume = 2.09L

Therefore, 2.09L of water is required.

The chemical formula of a compound describes the elements the compound contains and the
A.pH of the compound.
B.conduction of the compound.
C.ratio of elements in the compound.
D.ratio of neutrons to protons in each element.

Answers

Answer:

C.ratio of elements in the compound.

Explanation:

A compound is a substance that constitutes two or more elements in a defined proportion. A chemical compound is different from another compound in what it contains i.e. elements. A chemical formula shows the elements contained in a specific compound. For example, the chemical formula of sodium chloride (NaCl) shows us that it contains Sodium (Na) and Chlorine (Cl) elements as represented by symbols.

In addition to this, a chemical formula also shows the ratio of each element that makes up the compound. An element can have more than one atom in a compound. For example, CaCl2 is the chemical formula for Calcium chloride and it shows is that the ratio of Calcium (Ca) to Chlorine (Cl) is 1:2.

The correct answer is C, the ratio of elements in the compound.

 

Compound:-

A compound is a substance that constitutes two or more elements in a defined proportion. A chemical compound is different from another compound in what it contains i.e. elements.

Chemical formula:-It shows the elements contained in a specific compound. For example, the chemical formula of sodium chloride (NaCl) shows us that it contains Sodium (Na) and Chlorine (Cl) elements as represented by symbols. A chemical formula also shows the ratio of each element that makes up the compound. An element can have more than one atom in a compound. For example, [tex]MgCl_2[/tex] is the chemical formula for Magnesium chloride and it shows that the ratio of Magnesium to Chlorine (Cl) is 1:2.

Hence, the correct answer is C.

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A student dissolves 1 g of sugar in 10 g of water she then determines the mass of the solution what is the mass of dissolved sugar and water

Answers

Answer:

11grams

Explanation:

Use the law '' conversation of mass ''

Because the sugar dissolved in water.

Cheers! :D

PS: Mark me as brianest. Thx.

A. Element
B. Compound
C homogenous mixture
D heterogenous mixture

Answers

Is the letter A is an element

CH3CH2CHCH2 + HCl in iupac

Answers

Answer:

But-1-ene and Hydrochloric acid

Explanation:

CH3CH2CHCH2

H        H          H

H - C- C - C = C

H        H          H

C - Carbon

H - Hydrogen

But-1-ene

H - Cl

H - Hydrogen = 1+ = Hard Acid

Cl - Chlorine = 1- = Hard Base

Hydrochloric acid

The English system is used as the International System of Measurement. Please select the best answer from the choices provided T F

Answers

FALSE


explanation: the English system of measurement is mainly only used in England. The metric system is the international system of measurement.
False it’s the metric system

Acid, Base, or Saft?
USE THE ARRHENIUS DEFINITION TO CLASSIFY IF THE SUBSTANCE IS AN ACID, BASE, OR SALT
» MgF2
» H2SO4

Answers

Answer:

MgF2 - Salt

H2SO4 - Acid

Explanation:

Arrhenius Definition

Arrhenius acid is a substance that dissociates in water to form hydroxide (H+) ions.

Arrhenius base is a substance that dissociates in water to form hydroxide (OH–) ions.

H+

OH-

S2-

O2-

MgF2 - Salt as no Hydrogen

H2SO4 - Acid as converts to HSO4- and H+ upon dissociation in water.

In the reaction, HCl + H2O produces H3O + Cl, what is the conjugate acid

Answers

Answer:

Conjugate acid is H3O

Explanation:

HCl + H2O = H3O + Cl

HCl = H+ and Cl- = Acid

H2O = OH- and H+ = Neutral as equal OH- and H+

H3O = H3O+ = Acid also known as Hydronium

Cl = Just free floating Chlorine = Cl-

Conjugate acid is H3O

Acid = A solution with more H+ ions than OH- ions.

An experimental procedure says to accurately weigh approximately 1 g of
substance on analytical balance. Which of the following measurements are
consistent with these instructions? Select all that apply.
1.0456 g
1.0 g
0.9811g
1 g
1.01g
O 0.99

Answers

Answer:

1.0456 g and 0.9811g

Explanation:

The measurements that are consistent with the approximate 1 g instruction would be 1.0456 g and 0.9811g.

Analytical balance generally weighs to an accuracy of 4 decimal places. Hence, every other option that is short of being in 4 decimal places is incorrect.

Also, 1.0456 g and 0.9811g when approximated to the nearest whole number give 1 g.

Nonrenewable resources are ?

Answers

DescriptionA non-renewable resource is a natural resource that cannot be readily replaced by natural means at a quick enough pace to keep up with consumption. An example is carbon-based fossil fuel

Answer:

limited resources

Explanation:

nonrenewable resources are those resources found inside the earth that are in a fixed amount. They are being used at a faster rate, and cannot be renewed. These resources include fossil fuels,natural gas, and coal.

// have a great day //

Values for the molar mass of nitrogen, oxygen, and nitrogen dioxide molecules are given in the table below. What mass of nitrogen dioxide molecules is formed when 1 mole of nitrogen reacts with 2 moles of oxygen and forms nitrogen dioxide? Choices: A). 92.02g B). 46.01g C). 23.00g D) 2.00g

Answers

Answer:

A). 92.02g

Explanation:

Equation of the reaction;

N2 (g)+ 2O2(g)------> 2NO2(g)

Note that the balanced reaction equation is the first step in solving any problem on stoichiometry. Once the reaction equation is correct, the question can be easily solved.

Reaction of one mole of nitrogen gas with two moles of oxygen gas yields two moles of nitrogen dioxide.

Mass of two moles of nitrogen dioxide= 2[14 + 2(16)] = 2[14+32]= 2[46]= 92 gmol-1

Therefore; Mass of two moles of nitrogen dioxide is 92

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Question 10 Multiple Choice Worth 3 points)
(05.03 MC)
A glass of juice at 20°C was kept in the open. After 30 minutes, the temperature of the juice remained the same. Which statement is correct?
The temperature of the surrounding air was greater than 20 °C.
The temperature of the surrounding air was less than 20 °C.
The temperature of the juice was equal to the temperature of the surrounding air.
The temperature of the juice was less than the final temperature of the surrounding air.

Answers

Answer:

The answer would be B the temperature of the juice was the temperature of the surrounding air...trust me lolllllllllllllllll

If 11 moles of A are combined with 16 moles of B and the reaction occurs to the greatest extent possible, how many moles of C form?

Answers

it would be 7.3 mol c

Horned animals have different sizes of horns. The size of their horns can affect their ability to
compete for a mate or provide protection from predators,
What is this an example of?
overproduction
O variation
survival of fit individuals

Answers

Answer:

survival of fit individuals

Explanation:

I believe its survival of fit individuals because the animals with different horns are going to be able to find a mate or provide better depending on their horn and its kind of like natural selection in the sense those who have genetically better (??) horns are more likely to survive.  Hope it helps but it might be a little bit of a confusing explanation.

Answer:

variation

Explanation:

survival of the fittest, is more like, "out of 3 people only 1 makes it"

^ so the other guy is wrong.

What is one way in which chemistry affects your everyday life?
A. Refrigerators use energy more efficiently than they did 10 years
ago.
B. Tap water is safe to drink because it is monitored for harmful
substances.
c. Weather forecasts are now more accurate because of radar.
D. Watches are now more accurate because they are digitalized.

Answers

Answer: B

Explanation: Water is filtered with a bunch of chemicals which makes it drinkable.

B, the filtration system used to make drinking water safe consists of chemistry

Classify the following as an element, compound, homogeneous mixture, or heterogeneous


mixture: salt water

A. Element
B. Compound
C. Homogeneous mixture
D. Heterogenous mixture

Answers

The answer is D. Heterogeneous mixture

hi:) how to do 2(bi)?

Answers

Answer:

4 protons, 5 neutrons, 2 electrons

Explanation:

If you look at the numbers beside Be²⁺, the number 9 is the relative atomic mass and the number 4 is the proton (atomic) number. The relative atomic mass is the sum of the number of protons and the number of neutrons.

Number of protons= proton number.

Hence, number of protons= 4

Number of protons + neutrons= 9

4 + number of neutrons= 9

number of neutrons

= 9 -4

= 5

In an atom, the number of protons and electrons are the same since atoms are electrically neutral. But in an ion, the number of electrons is not equal to the number of protons since the atom gains/ loses electrons to form an ion. A positive sign means that electrons are given away.

Thus, Be gives away 2 electrons to form Be²⁺.

Original number of electrons= 4

Number of electrons in Be²⁺

= 4 -2

= 2

In summary, the number of protons and neutrons in an ion is the same as that of the atom. However, the number of electrons is not the same.

Answer:

Answer:

4 protons, 5 neutrons, 2 electrons

Explanation:

If you look at the numbers beside Be²⁺, the number 9 is the relative atomic mass and the number 4 is the proton (atomic) number. The relative atomic mass is the sum of the number of protons and the number of neutrons.

Number of protons= proton number.

Hence, number of protons= 4

Number of protons + neutrons= 9

4 + number of neutrons= 9

number of neutrons

= 9 -4

= 5

In an atom, the number of protons and electrons are the same since atoms are electrically neutral. But in an ion, the number of electrons is not equal to the number of protons since the atom gains/ loses electrons to form an ion. A positive sign means that electrons are given away.

Thus, Be gives away 2 electrons to form Be²⁺.

Original number of electrons= 4

Number of electrons in Be²⁺

= 4 -2

= 2

In summary, the number of protons and neutrons in an ion is the same as that of the atom. However, the number of electrons is not the same.

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What causes blood pressure?
A.the strength of the muscles in the walls of the capillaries
B.the speed at which oxygen is returned to blood in the lungs
C. the force with which the ventricles contract
D. the rate at which blood flows through the heart

Answers

Answer:

C

Explanation:

What causes blood pressure?

C

To pump blood around the body, the heart contracts and then relaxes through the cardiac cycle. The cycle begins with the contraction of the two atria, which push blood into the ventricles. Then, the ventricles contract, which forces the blood out of the heart.

When the heart pushes blood around the body during systole, the pressure placed on the vessels increases. This is called systolic pressure.

When the heart relaxes between beats and refills with blood, the blood pressure drops. This is called diastolic pressure.

Which type of crystal is typified by a sea of delocalized electrons
surrounding the lattice?
O A. lonic
B. Metallic
OC. Macromolecular
D. Chemical
Reset Selection

Answers

B.metallic is the answer hope this helped

The correct answer is option B. Metallic.

What explains the structure of metals and delocalized electrons?

Metal is composed of a huge structure of atoms arranged in a regular pattern. Electrons from the outer shell of a metal atom are delocalized and can move freely throughout the structure. This sharing of delocalized electrons results in strong metal bonds.

Metallic bonds are electrostatic attraction between metal cations and the negatively charged ocean of delocalized electrons. The sea of ​​delocalized electrons contains only valence electrons, not core electrons.

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do rainforests have hot summers and cold winters?

Answers

Answer:

No, rainforests have long wet winters and short dry summers.

Tropical rainforests are lush and warm all year long! Temperatures don't even change much between night and day. The average temperature in tropical rainforests ranges from 70 to 85°F (21 to 30°C).

1. How many acetate ions are in the compound strontium acetate?

Answers

Answer: 2 Acetate ions

Explanation:

Strontium Acetate, has the molecular formular to be; C4H6O4Sr ( or in a linear form, Sr(CH3COO)2), contains two acetate ions.

In one molecule of strontium acetate (Sr(CH₃COO)₂), there are two acetate ions (CH₃COO⁻).

We must first comprehend the chemical composition of strontium acetate in order to calculate the quantity of acetate ions present.

Acetate ions (CH₃COO⁻) and strontium ions (Sr²⁺) combine to linear form the ionic compound strontium acetate. Sr(CH₃COO)₂ is the chemical formula for strontium acetate.

(CH₃COO)₂ stands for two acetate ions in the formula. The (CH₃COO⁻) ion, also referred to as the acetate ion, is a polyatomic ion made up of two carbon (C), three hydrogen (H), and two oxygen (O) atoms. It has a -1 charge overall.

Thus, there are two acetate ions (CH₃COO⁻) in a single molecule of strontium acetate (Sr(CH₃COO)₂).

It's crucial to understand that in ionic compounds like strontium acetate, the ratio of positively charged ions (cations) to negatively charged ions (anions) must be balanced in order to produce a neutral compound. In this instance, the two -1 charges of the acetate ions (CH₃COO⁻) counterbalance the two +2 charges of the strontium ions (Sr²⁺), creating a neutral molecule.

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Which of the following always occurs in a
chemical reaction?

A) a gas is given off.
B) a solid is produced,
C) a new substance is produced.
D) a colour change takes place.

Answers

Answer:

C

Explanation:All the other answers are wrong

What is the energy of light with a wavelength of 652 nm? (The speed of light in a vacuum is 3.00 x 108 m/s, and Planck's constant is 6.626 x 10-34 J·s.)
O A 3.05 x 10-²⁸ j
O B. 3.28 x 10¹⁸ j
O C. 3.05 x 10-¹⁹ j
D. 3.28 x 10²⁷ j

A and C have negative exponents pleas help me​

Answers

Answer:

C. 3.05 x 10⁻¹⁹ J

Explanation:

Given;

wavelength of the light, λ = 652 nm = 652 x 10⁻⁹ m

speed of light, c = 3.00 x 10⁸ m/s

Planck's constant, h = 6.626 x 10⁻³⁴J·s

Energy of electromagnetic wave is calculated as;

E = hf

where;

f is frequency of the light wave

f = c / λ

[tex]E = hf = h\frac{c}{\lambda} \\\\E = \frac{hc}{\lambda} \\\\E = \frac{6.626*10^{-34}*3*10^8}{652*10^{-9}} \\\\E = 3.05*10^{-19} \ J[/tex]

Therefore, the energy of the light is 3.05 x 10⁻¹⁹ J

The correct option is "C"

C. 3.05 x 10⁻¹⁹ J

Answer:

Option C. 3.05 x 10¯¹⁹ J

Explanation:

Step 1:

Data obtained from the question.

wavelength (λ) 652 nm = 652x10^–9m

Velocity of light (v) = 3.00x10^8 m/s

Planck's constant (h) = 6.626x10^-34J·s

Step 2:

Determination of the frequency of the light.

The frequency can be obtained as follow

v = λf

3x10^8 = 652x10^–9 x f

Divide both side by 652x10^–9

f = 3x10^8 / 652x10^–9

f = 4.6x10^14s¯¹

Step 3:

Determination of the energy of the light wave.

This can be obtained as follow:

Planck's constant (h) = 6.626x10^-34J·s

Frequency (f) = 4.6x10^14s¯¹

Energy (E) =..?

E = hf

E = 6.626x10^-34 x 4.6x10^14s¯¹

E = 3.05 x 10¯¹⁹ J

The volume of a gas is 450 mL when its pressure is 1.00 atm. If the temperature of the gas does not change, what is the
pressure when its volume is changed to 2.00 L?
Use PV = P2V2.
0.225 atm
O 0.444 atm
O 2.25 atm
O 4.44 atm

Answers

Answer: 0.225 atm

Explanation:

For this problem, we have to use Boyle's Law.

Boyle's Law: P₁V₁=P₂V₂

Since we are asked to find P₂, let's manipulate the equation.

P₂=(P₁V₁)/V₂

[tex]P_{2} =\frac{(1.00atm)(0.45L)}{2.00L}[/tex]

With this equation, the liters cancel out and we will be left with atm.

P₂=0.225 atm

What is amplitude in chemisty

Answers

Answer:

CHEMISTRY GLOSSARY

Amplitude is the displacement of a wave from zero. The maximum amplitude for a wave is the height of a peak or the depth of a trough, relative to the zero displacement line

When may a scientific theory be revised?

Answers

Answer:

it can be revised at any time.

Explanation:

Answer: Multiple answers to this question. This is what I comprehend.

Explanation:

Upon analysis of the results, a theory can be rejected or modified, but it can never be proven to be correct 100 percent of the time. For example, relativity has been tested many times, so it is generally accepted as true, but there could be an instance, which has not been encountered, where it is not true.

How is a muscle mutation potentially linked to the size of our brain?

Answers

Answer:

I found on internet may be it helps

Explanation:

Here, we provide a general review of recent studies into the genetic basis of human brain evolution. The insights gleaned from these studies can be broadly divided into three categories: (i) positive selection on protein-coding regions of the genome that lead to changes in the sequences of existing proteins; (ii) duplication and deletion of genes; and (iii) evolutionary changes in non-coding regions of the genome, especially those in cis-regulatory sequences that lead to altered gene expression .

Count then plot the total number of atoms in the reactants to total atoms
in the products for the equation 2H2 + O2 + 2H2O

Answers

answer C
explanation C

Need help, thank you!

Answers

Answer:

B the answer is B thank you

Latent heat of vaporization is used to (1 Point) (a) overcome the forces of attraction between molecules in solid-state. (b) increase the kinetic energy of molecules in a liquid state. (c) overcome the forces of attraction between molecules in a liquid state. (d) increase the kinetic energy of molecules in the vapour state.

Answers

Answer:

Not sure what the answer is

Explanation:

I did this a while ago and dont remember sorry

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