All categories

3 years ago

The radioisotope radon-222 has a half life of 3.8 days. How much of a 10 gram sample of radon-222 would be left after 15.2 days?

Chemistry

1 answer:

djyliett [7]3 years ago

4 0

Answer:

0.625 g

Explanation:

Given data:

Half life of radon-222 = 3.8 days

Total mass of sample = 10 g

Mass left after 15.2 days = ?

Solution:

Number of half lives = T elapsed / Half life

Number of half lives = 15.2 / 3.8

Number of half lives = 4

At time zero = 10 g

At first half life = 10 g/2 = 5 g

At 2nd half life = 5 g/ 2= 2.5 g

At third half life = 2.5 g/2 = 1.25 g

At 4th half life = 1.25 g/2 = 0.625 g

You might be interested in

A certain substance X has a normal freezing point of -6.4 C and a molal freezing point depression constant Kf= 3.96 degrees C.kg

Brut [27]

Answer: $1.0\times 10^2g$

Explanation:

Depression in freezing point is given by:

$\Delta T_f=i\times K_f\times m$

$\Delta T_f=T_f^0-T_f=(-6.4-(13.6))^0C=7.2^0C$ = Depression in freezing point

i= vant hoff factor = 1 (for non electrolyte like urea)

$K_f$ = freezing point constant = $3.96^0C/m$

m= molality

$\Delta T_f=i\times K_f\times \frac{\text{mass of solute}}{\text{molar mass of solute}}\times \text{weight of solvent in kg}}$

Weight of solvent (X)= 950 g = 0.95 kg

Molar mass of non electrolyte (urea) = 60.06 g/mol

Mass of non electrolyte (urea) added = ?

$7.2=1\times 3.96\times \frac{xg}{60.06 g/mol\times 0.95kg}$

$x=1.0\times 10^2g$

Thus $1.0\times 10^2g$ urea was dissolved.

8 0

3 years ago

A bowling ball and basketball collide, what direction do they go and how is energy transferred?

olga nikolaevna [1]

Answer:

When the batter hits the ball, there is a force applied, and energy is transferred. The ball will move in the direction the force is pushing it. If two objects collide, energy will be transferred between both, and there will be a change in motion.

Explanation:

8 0

2 years ago

A substance has a volume of 10.0 cm3 and a mass of 89 grams. What is its density?

AlladinOne [14]

8.9 g/cm3 since density equals mass/volume or m/v you just divide 89 by 10 to get 8.9

4 0

3 years ago

Read 2 more answers

Which of the following is not a part of Earth’s system? a. hydrosphere b. geosphere c. biosphere d. chronosphere

Citrus2011 [14]

It is D.chronoshpere

5 0

3 years ago

Read 2 more answers

The molecular mass of sodium oxide (Na2O) is

yuradex [85]

<span>The molecular mass of sodium oxide (Na2O) is A. 61.97894. The molecular mass of a molecule (Mr) is the sum of atomic masses of its atoms (Ar). The molecular mass of sodium oxide is: Mr(Na2O) = 2 * Ar (Na) + Ar(O). From the periodic table, Ar(Na) = 22.989769 and Ar(O) = 15.9994. The molecular mass of sodium oxide is: Mr(Na2O) = 2 * 22.989769 + 15.9994 = 45.979538 + 15.9994 = 61.97894.</span>

6 0

3 years ago