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2 years ago

If the half life of a radioactive isotope is 1 day, then how much of the original isotope remains at the end of two days?

Chemistry

2 answers:

ikadub [295]2 years ago

8 0

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25%

Explanation:

In a half life of a radioactive isotope is 1 day,it means it loses its half mass each day

We a formula for N half life

$\sf { \frac{1}{2} }^{n}$

where n is the number of days

Here the isotope is kept for 2 days

so it's left over mass will be

$\sf { (\frac{1}{2}) }^{2} \\ \\ \\ \frac{1}{2} \times \frac{1}{2} \\ \\ \sf \frac{1}{4}$

It's left over mass 1/4th of the original mass

Now, we need to find it's percentage by multiplying with 100

$\sf \frac{1}{4} \times 100 \%\\ \\ \sf \cancel\frac{100}{4} \% \\ \\ \sf 25\%$

So 25% mass will be left after 2 day of half life radioactive isotope.

JulijaS [17]2 years ago

8 0

25% because the half life of 100 is 50 and the half life of 50 is 25

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A theater director reinterprets a play by replacing its classical score with

cricket20 [7]

Answer:

The play will be more appealing to a younger audience.

Explanation:

A younger audience will more likely appreciate current pop hits rather than classical score.

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3 years ago

Read 2 more answers

How many moles of solute are contained in a 250.0-milliliter solution that has a concentration of 0.85 M?

adoni [48]

Answer : The correct option is, 0.21 moles

Solution : Given,

Molarity of the solution = 0.85 M = 0.85 mole/L

Volume of solution = 250 ml = 0.25 L $(1L=1000ml)$

Molarity : It is defined as the number of moles of solute present in one liter of the solution.

Formula used :

$Molarity=\frac{\text{moles of solute}}{\text{Volume of solution in liters}}$

Now put all the given values in this formula, we get the moles of solute of the solution.

$0.85mole/L=\frac{\text{moles of solute}}{0.25L}$

$\text{moles of solute}=0.2125=0.21moles$

Therefore, the moles of solute is, 0.21 moles

7 0

3 years ago

Read 2 more answers

In an acid-base titration, a student uses 21.35 mL of 0.150 M NaOH to neutralize 25.00 mL of H2SO4. How many moles of acid are i

GalinKa [24]

Answer: There are 0.006 moles of acid in the flask.

Explanation:

Given: $V_{1}$ = 21.35 mL, $M_{1}$ = 0.150 M

$V_{2}$ = 25.0 mL, $M_{2}$ = ?

Formula used to calculate molarity of $H_{2}SO_{4}$ is as follows.

$M_{1}V_{1} = M_{2}V_{2}$

Substitute the values into above formula as follows.

$M_{1}V_{1} = M_{2}V_{2}\\0.15 M \times 21.35 mL = M_{2} \times 25.0 mL\\M_{2} = 0.1281 M$

As molarity is the number of moles of a substance present in a liter of solution.

Total volume of solution = $V_{1} + V_{2}$

= 21.35 mL + 25.0 mL

= 46.36 mL (1 mL = 0.001 L)

= 0.04636 L

Therefore, moles of acid required are calculated as follows.

$Molarity = \frac{no. of moles}{Volume (in L)}\\0.1281 M = \frac{no. of moles}{0.04635 L}\\no. of moles = 0.006 mol$

Thus, we can conclude that there are 0.006 moles of acid in the flask.

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3 years ago

Describe the particle that is emitted during alpha decay. How do you think an atom changes when it undergoes alpha decay?

weqwewe [10]

Answer:

Helium nuclei is emitted during alpha decay.

Explanation:

Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number 4 less than and atomic number 2 less than the starting atom.

Properties of alpha radiation:

Alpha radiations can travel in a short distance.

These radiations can not penetrate into the skin or clothes.

These radiations can be harmful for the human if these are inhaled.

These radiations can be stopped by a piece of paper.

Example:

₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴ + energy

8 0

3 years ago

I need help with this!!

8_murik_8 [283]

Answer:

0.84kg of gatorade powder is needed.

Explanation:

From the question given above, we were told that the team manager mixes 0.6kg of gatorade powder with 5 gallons of water.

Now, to obtain the desired amount of the powder of gatorade needed for 7 gallons of water, we simply do the following:

If 0.6kg of gatorade powder required 5 gallons of water,

Then Xg of gatorade will require 7 gallons of water i.e

Xg of gatorade = (0.6 x 7)/5

Xg of gatorade = 0.84kg

Therefore, to maintain the same gatorade mixture, the team manager must mix 0.84kg of gatorade powder with the 7 gallons of water.

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3 years ago