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zlopas [31]
2 years ago
12

What is the half-life of a radioisotope if it decays to 25% of its original activity in 7 yr?

Chemistry
1 answer:
Pepsi [2]2 years ago
7 0

Answer:

3.5 yrs

Explanation:

If a sample has decayed to 25%, this means 2 half-lives have passed. We are given this is equal to 7 yrs, and it follows that one half life is 3.5 yrs.

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A sample of air at 58.6 kPa is expanded from 250 mL to 655 mL. If thetemperature remains constant, what is the final pressure in
kati45 [8]

Answer:

<h2>22.366 kPa</h2>

Explanation:

The final pressure can be found by using the formula for Boyle's law which is

P_1V_1 = P_2V_2

Since we are finding the final pressure

P_2 =  \frac{P_1V_1}{V_2}  \\

From the question

58.6 kPa = 58600 Pa

We have

P_2 =  \frac{58600 \times 250}{655}  =  \frac{14650000}{655}  \\  = 22366.4122... \\  = 22366

We have the final answer as

<h3>22.366 kPa</h3>

Hope this helps you

3 0
3 years ago
Which of the following is a renewable resource?
Sergeeva-Olga [200]
Answer: A wood
I hope this helps you
5 0
3 years ago
Read 2 more answers
Empirical formula of 25.13g sulfur and 49.87g copper
antiseptic1488 [7]

Copper + sulfur create copper sulfide.

It's a lengthy process to find the empirical formula:

Sulfur:

25.13g * \frac{1 mol}{32.065 g} = 0.78 mol

Copper:

49.87 * \frac{1 mol}{63.546 g} = 0.78mol

S:Cu => \frac{0.78}{0.78} :\frac{0.78}{0.78} => (1:1) * 1 => 1:1

The empirical formula would just be CuS

7 0
3 years ago
Why do we use anhydrous diethyl ether? Choose the right answer.
grigory [225]

Answer:    

The answer is <em>B</em>

Explanation:

4 0
4 years ago
On a lab exam, you have to find the concentrations of the monoprotic (one proton per molecule) acids HA and HB. You are given 43
Keith_Richards [23]

HA and HB are present in concentrations of 0.182 M and 0.153 M, respectively.

<h3>What kind of acids are monoprotic?</h3>

Monoprotic acids include benzoic acid (C6H5CO2H), acetic acid (CH3CO2H or HOAc), nitric acid (HNO3), and hydrochloric acid (HCl).

<h3>How can you tell if a substance is monoprotic?</h3>

Any acid with only one hydrogen atom in its formula is called a monoprotic acid, while some acids with multiple hydrogen atoms may also fall under this category. In other words, while all monoprotic acids contain only one hydrogen, not all single-hydrogen acids are monoprotic.

<h3>Do monoprotic acids have a low acidity?</h3>

Because it easily loses its hydrogen ion in solution, the monoprotic acid HBr is regarded as being strong.

learn more about  monoprotic acid here

brainly.com/question/12850710

#SPJ4

5 0
2 years ago
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