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3 years ago

Which statements correctly describe the decay rates of radioactive isotopes?

Chemistry

2 answers:

Svetllana [295]3 years ago

6 0

Answer:

For plato, the answer is C: after each half tile, the amount of radioactive material is reduced by half

storchak [24]3 years ago

4 0

Answer: b} The exact time when an individual atom will decay can be accurately predicted.

c} After each half-life, the amount of radioactive material is reduced by half.

Explanation:

All radioactive decay follows first order kinetics.

Rate law expression for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant

t = time taken for decay process

a = initial amount of the reactant

a - x = amount left after decay process

Expression for calculating half life, which is the time taken by the half of the reactants to decompose is:

$t_{1/2}=\frac{0.693}{k}$

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3 years ago

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2 points

Westkost [7]

Answer:

Law of conservation of mass

Ernest Rutherford

Explanation:

The basic law of behavior of matter that states that "mass is neither created nor destroyed in a chemical reaction or physical change".

This is the law of conservation of mass. It is very essential in understanding most chemical reaction. Also, in quantitative analysis, this law is pivotal.

Ernest Rutherford was the scientist that stated that the nucleus is made up of positive charge. It was not until James Chadwick in 1932 discovered the neutron that we had an understanding of this nuclear component.

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3 years ago

Do metals form are anions or cations?

goldfiish [28.3K]

Answer: Metals form cations.

The alkali metals (the IA elements) lose a single electron to form a cation with a 1+ charge.

The alkaline earth metals (IIA elements) lose two electrons to form a 2+ cation.

Aluminum, a member of the IIIA family, loses three electrons to form a 3+ cation.

Therefore, metals in the s and p block of the periodic table have 1, 2 or 3 electrons in their outermost orbit (or valence shell). Now to gain a stable octet metals lose either 1, 2 or 3 electrons from the valence shell thus forming cation with +1, +2 or +3 charge.

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3 years ago

A 0.4322 g sample of a potassium hydroxide – lithium hydroxide mixture requires 27.10 mL of 0.3565 M HCl for its titration to th

Yuki888 [10]

The mass percent lithium hydroxide in the mixture with potassium hydroxide, calculated from the equivalence point in the titration of HCl with the mixture, is 19.0%.

The mass percent of lithium hydroxide can be calculated with the following equation:

$\% = \frac{m_{LiOH}}{m_{t}} \times 100$ (1)

Where:

$m_{t} = m_{KOH} + m_{LiOH} = 0.4322 g$ (2)

We need to find the mass of LiOH.

From the titration, we can find the number of moles of the mixture since the number of moles of the acid is equal to the number of moles of the bases at the equivalence point.

$\eta_{HCl} = \eta_{LiOH} + \eta_{KOH}$