All categories

2 years ago

Fluorine-21 has a half-life of approximately 5 seconds. what percentage of the original nuclei would remain after 15 seconds

Chemistry

1 answer:

BlackZzzverrR [31]2 years ago

8 0

Answer:

1/8th = 12.5%

Explanation:

Three half lives would be 1/2 * 1/2 * 1/2 = 1/8 th of original

You might be interested in

If you sprayed an air freshener, where would the highest concentration of air freshener be found?

Hunter-Best [27]

FLOOR. Most of the molecules that dont sick to something fall on the floor so most would be on the FLOOR.

7 0

2 years ago

A sample of argon gas has a volume of 795 mL at a pres-sure of 1.20 atm and a temperature of 116 ∘C. What is the final volume of

jek_recluse [69]

<u>Answer:</u> The volume when the pressure and temperature has changed is $1.6\times 10^2mL$

<u>Explanation:</u>

To calculate the volume when temperature and pressure has changed, we use the equation given by combined gas law.

The equation follows:

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

where,

$P_1,V_1\text{ and }T_1$ are the initial pressure, volume and temperature of the gas

$P_2,V_2\text{ and }T_2$ are the final pressure, volume and temperature of the gas

Let us assume:

$P_1=1.20atm\\V_1=795mL\\T_1=116^oC=[116+273]K=389K\\P_2=0.55atm\\V_2=?mL\\T_2=75^oC=[75+273]K=348K$

Putting values in above equation, we get:

$\frac{1.20atm\times 795mL}{389K}=\frac{0.55atm\times V_2}{348K}\\\\V_2=\frac{1.20\times 795\times 348}{0.55\times 389}=1.6\times 10^3mL$

Hence, the volume when the pressure and temperature has changed is $1.6\times 10^2mL$

5 0

2 years ago

Explain how thermal energy is transferred in convection.

Tpy6a [65]

Answer:

Convection occurs when particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat energy. Heat energy is transferred from hot places to cooler places by convection. Liquids and gases expand when they are heated. ... As a result, the particles take up more volume.

4 0

2 years ago

Number of neutrons for 9BE4

GREYUIT [131]

Mass number - # of protons = #neutrons, so I would say the answer is 5

8 0

2 years ago

In central Texas, in the area known as the Texas Hill Country, is the Edwards Plateau ecoregion and Llano Uplift ecoregion. The

ra1l [238]

Answer: chemical weathering

Explanation:

8 0

2 years ago