All categories

3 years ago

If a substance has a half life of 58 years and starts with 500 g radioactive, how much remains radioactive after 30 years?

Chemistry

1 answer:

Vilka [71]3 years ago

5 0

Answer:

A = 349 g.

Explanation:

Hello there!

In this case, since the radioactive decay kinetic model is based on the first-order kinetics whose integrated rate law is:

$A=Ao*exp(-kt)$

We can firstly calculate the rate constant given the half-life as shown below:

$k=\frac{ln(2)}{t_{1/2}} =\frac{ln(2)}{58year}=0.012year^{-1}$

Therefore, we can next plug in the rate constant, elapsed time and initial mass of the radioactive to obtain:

$A=500g*exp(-0.012year^{-1} *30year)\\\\A=349g$

Regards!

You might be interested in

How to determine how many valence electrons an element has?

In-s [12.5K]

Usually (ignoring transition metals, as they kinda get trickier), the element's valency can be found out by its group (column) number. Usually, we ignore the transition metal block while counting these columns, so Aluminium is in group 3, for example. Since Aluminium is in group 3, it has 3 valence electrons.

8 0

3 years ago

The following are steps in the process of cloning a mouse. Arrange the steps in the correct order. (8.L.2.1) *

andrezito [222]

Answer:

Explanation:

I got A wrong so maybe

8 0

2 years ago

The average lung capacity of a human is 6.0L.

Darya [45]

Answer:

(a) 0.25 mol

(b) 0.11 mol

Explanation:

(a)

We use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of the gas = 1.00 atm

V = Volume of the gas = 6.0 L

T = Temperature of the gas = 298 K

R = Gas constant = $0.0821\text{ L.atm }mol^{-1}K^{-1}$

n = number of moles = ?

Putting values in above equation, we get:

$1.00 atm\times 6.0L=n\times 0.0821\text{ L.atm }mol^{-1}K^{-1}\times 298K\\\\n=\frac{1.00\times 6.0}{0.0821\times 298}=0.25mol$

(b)

We use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of the gas = 0.296 atm

V = Volume of the gas = 6.0 L

T = Temperature of the gas = 200 K

R = Gas constant = $0.0821\text{ L.atm }mol^{-1}K^{-1}$

n = number of moles = ?

Putting values in above equation, we get:

$0.296 atm\times 6.0L=n\times 0.0821\text{ L.atm }mol^{-1}K^{-1}\times 200K\\\\n=\frac{0.296\times 6.0}{0.0821\times 200}=0.11mol$

(c)

We use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of the gas = 30 atm

V = Volume of the gas = 6.0 L

T = Temperature of the gas = 250 K

R = Gas constant = $0.0821\text{ L.atm }mol^{-1}K^{-1}$

n = number of moles = ?

Putting values in above equation, we get:

$30 atm\times 6.0L=n\times 0.0821\text{ L.atm }mol^{-1}K^{-1}\times 250K\\\\n=\frac{30\times 6.0}{0.0821\times 250}=8.77mol$

8 0

3 years ago

Identify a cation. Group of answer choices an atom that has lost a proton. an atom that has gained an electron an atom that has

pshichka [43]

Answer: An atom that has gained an electron.

Explanation:

The number of protons in an atom cannot change except for some exceptional circumstances.

Cations (or metal ions) are formed when atoms lose electrons, as they want to form a complete outer electron shell to become as stable as possible.

For example, potassium is a 1+ ion, because it has one electron in its outer shell (and in group one). Therefore, to become more stable that electron is lost to become an ion or cation. As one electron is lost, the potassium cation charge is 1+ as the charge of an electron is 1-.

3 0

2 years ago

How do i fill out this ICE chart? please help

LuckyWell [14K]

Answer: You can probably go onto You Tube and find that answer! Just be detailed in your search! Hope this helps!

Explanation:

Just Simple Physics :P

3 0

2 years ago

Read 2 more answers