What percentage of a substance remains after 7 half-lives have passed?
A. 0.39
B. 2.5
C. 1.25
D. 0.78

Answers

Answer 1

Answer:

Not really sure, buts its either B or C.


Related Questions

Two reasons that a plant from a rain forest would not survive in a desert home?

Answers

Answer: A planet from a rain forest would not survive in a desert home, for the fact they depend on water and as these live from water, without it, this leads to dehydration and with loss of water with plants, nothing is able to survive when it comes to a rain forest plant being in a desert home. Another reason is the high trees and leaves that are providing the plants enough sunlight or shade to grow, it guarantees to help keep the temperature normal. Being in a deserted area would mean that there would be a temperature change, something the plant is not used to. Without that needed shade and avoiding the scorching sun, they will die out from how different the temperature is, and how hot it is.

Explanation: I hope this helped you.

okay, the answer should be simple and easy, plants from a rainforest would not survive in a desert because the plants in the rainforest do get water, sunlight and air whereas the plants in the desert have Sunlight which is very hot. so if a plant in the rainforest was transferred to the desert it will hard to survive and it will eventually die because they will not get water that will be needed and the plant can get sunburns with the too hot temperature.

What is the number of moles in a sample of gas that has a volume of 3.5 L, a
pressure of 200 kPa, and a temperature of 300 K?

Answers

Explanation:

[tex]PV = nRT \\ (200000 \times 3.5 \times {10}^{ - 6} ) = n \times 8.314 \times 300 \\ n = \frac{0.07}{2494.2 } \\ n = 2.81 \times {10}^{ - 5} [/tex]

[tex] \small{ \star{ \underline{ \blue{ becker}}}}[/tex]

Whilst Et₃CCl is unreactive towards water even at elevated temperatures, Et₃SiCl is hydrolyzed rapidly. Explain the origin of these differences and provide a reaction scheme with mechanistic details for the hydrolysis of Et₃SiCl.

Answers

Answer:

See Explanation

Explanation:

In discussing the reason why Et₃SiCl is more easily hydrolysed than Et₃CCl, we must remember that the electronegativity difference between silicon and chlorine is much higher than the electronegativity difference between carbon and chlorine.

As a result of this, the Si-Cl bond in Et₃SiCl is more polar and hence susceptible to attack by water than the C-Cl bond in Et₃CCl.

Also, it is postulated that the presence of vacant d orbitals on silicon assists hydrolysis in Et₃SiCl. Such vacant orbitals are absent in carbon hence Et₃CCl does not undergo hydrolysis.

The reaction scheme is shown in the image attached to this answer.

Using the balanced equation for the next few questions: 4 Fe(s) + 30 (9) - 2Fe2O3(s)
How many moles of Iron (11) Oxide would be produced by complete reaction of 0.15
moles of iron? (Be sure to show your work including the mole ratio you used)

Answers

Answer:

0.075 moles of iron oxide would be produced by complete reaction of 0.15  moles of iron.

Explanation:

The balanced reaction is:

4 Fe + 3 O₂ → 2 Fe₂O₃

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

Fe: 4 molesO₂: 3 molesFe₂O₃: 2 moles

You can apply the following rule of three: if by stoichiometry 4 moles of Fe produce 2 moles of Fe₂O₃, 0.15 moles of Fe produce how many moles of Fe₂O₃?

[tex]moles of Fe_{2} O_{3} =\frac{0.15 moles of Fe*2 moles of Fe_{2} O_{3} }{4 moles of Fe}[/tex]

moles of Fe₂O₃= 0.075

0.075 moles of iron oxide would be produced by complete reaction of 0.15  moles of iron.

Select the correct mass for each of the samples described below.

3.01 × 1023 molecules H2O

Answers

Answer:

9.00 g H2O

Explanation:

Convert molecules to grams using stoichiometry

(3.01 * 10^23 molecules) * (1 mole H2O / 6.022 * 10^23 molecules) * (18.01 g / 1 mole H2O) = 9.00 g H2O

Answer:

answer  in picture

Explanation:

What volume of 15.9 M Nitric acid would be required to make 7.2 L of 6.00 M nitric acid? (hint: dilution problem) will mark brainliest if correct

a. 2.72 L
b. 686.88 L
c. .075 L
d. 272

Answers

Answer:

d

Explanation:

Calculate how many grams of sodium chloride we would need to make a solution with the same molarity of seawater, which is about 0.598 M.

Answers

Answer:

34.92 grams NaCl (in 1 L of solution)

Explanation:

The chemical formula of sodium chloride is NaCl. From the formula, we can calculate the molar mass of NaCl:

MM(NaCl)= MM(Na) + MM(Cl) = 23 g/mol + 35.4 g/mol = 58.4 g/mol

A solution of NaCl with a molarity of 0.598 M has 0.598 moles of NaCl per liter of solution. So, we multiply the moles by the molar mass of NaCl to calculate the mass we need:

mass of NaCl = 0.598 mol x 58.4 g/mol = 34.92 g NaCl

Therefore, we need 34.92 grams of NaCl to prepare 1 liter of a solution with a molarity of 0.598 M.

Which is true for a substance that releases energy?
OA. The energy release decreases the molecular motion and the kinetic energy of the substance.
B. The energy release decreases the molecular motion but increases the kinetic energy of the substance.
C. The energy release increases the molecular motion and the kinetic energy of the substance.
D. The energy release increases the molecular motion but decreases the kinetic energy of the substance.
E. The energy release is used only to change the state of the substance.

Answers

I’m not sure but I think it’s the first one

A Chemist reacted magnesium and aluminum oxide. A reaction takes place. Explain why

Answers

Explanation:

when Magnesium is reacted with Aluminum oxide, Aluminum being a less reactive metal than magnesium, is replaced by magnesium

Al2O3 + 3Mg - 3MgO + 2Al

hence reaction takes place

If two half lives have passed since a scientist collected a 1.00- gram sample of a U-235, how much U-235 is left now?

answers for most finals chem test questions (10th)

Answers

Answer:

one quarter of the original amount, so 0.25 g

Explanation:

Answer:

C

Explanation:

The reaction between solid aluminum and liquid bromine is exothermic. This reaction creates
the product aluminum bromide.
What equation includes the correct formulas and demonstrates conservation of mass?
A Al(s) + Br2(1) - AlBr3(s)
B Al(s) + Br(l) - AlBr(s)
C Al(s) + 3Br(1) - AlBr3(s)
D
2Al(s) + 3Br2(1) - 2AlBr3(s)

Answers

Answer:

correct answer is d)

Explanation:

This answer demonstrates law of conservation of mass because the mass of the products is equal to the mass of reactants with the help of the coefficients which is the process known as balancing. This answer also includes the correct formulas, as Br is a gas so it MUST be written as Br2. hope this helps:)

2Al(s) + 3Br2(1) - 2AlBr3(s) is the  correct formulas and demonstrates conservation of mass.

What is Conservation of Mass?

Every action has an equal and opposite response, states Newton's Third Law. This indicates that any force applied to an item will have an equal and opposite-directed response force of the same magnitude. A force pair is the collective name for these connected forces.

Each individual object will have a different force pair with each other object in systems of numerous objects where all things interact. In the case of charged particles, the charge of each object will dictate the direction of each force in the force pair.

Similar charges will cause particles to repel one another by directing their forces away from one another. With their forces pointing in the same direction, particles with opposing charges attract one another.

Therefore, 2Al(s) + 3Br2(1) - 2AlBr3(s) is the  correct formulas and demonstrates conservation of mass.

To learn more about mass, refer to the link:

https://brainly.com/question/19694949

#SPJ2

What would make oppositely charged objects attract each other more?
increasing the positive charge of the positively charged object and increasing the negative charge of the negatively
charged object
decreasing the positive charge of the positively charged object and decreasing the negative charge of the negatively
charged object
increasing the distance between the positively charged object and the negatively charged object
maintaining the distance between the positively charged object and the negatively charged object

Answers

Answer: increasing the positive charge of the positively charged object and increasing the negative charge of the negatively charged object.

Explanation:

edge

Answer:

Your answer is A.

Explanation:

how do I calculate the density

Answers

the equation would be p=m/v so...
A) 1.1 g/cm^3
B) .95 g/cm^3
C) 1 g/cm^3
i hope this helps!!!

That big lorry hit the new car.change to passive voice​

Answers

I don’t understand the question? Maybe try rewording it?

Convert 22 grams of copper Il chloride (Cucl2) to moles.
with work please ​

Answers

hope this helps!

https://youtu.be/MT5tKijKZwQ
Just click on there link the person gave

What is catalyst? Write its types.​

Answers

Answer:

A catalyst is a chemical substance that alters the rate of chemical reaction not consumed by the reaction. Hence, a catalyst can be recovered chen unchanged at the ends of chemical reaction. Catalyst can be divided into two typ the basis whether it speeds up or slowdowns the rate of chemical reaction. The positive catalyst and negative catalyst.

Answer:

A catalyst is a chemical substance thatalters therate of chemical reactions not consumed by the reactions.

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