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Alex777 [14]
3 years ago
12

What percentage of strontium-90 remains in a sample after three half-lives have passed? 12.5% 15% 25% 60%?

Chemistry
2 answers:
AnnyKZ [126]3 years ago
7 0

Answer:

12.5%

Explanation:

The half life of any reaction is the amount of time it takes to consume half of the starting material.

In this case, the original or starting percentage of material is 100%

100% - 50% : First Half Life

50% - 25%   : Second Half life

25% - 12.5% : Third Half life.

After three half lives have passes, the percentage of strontium-90 that remains in a sample is 12.5%

Lyrx [107]3 years ago
4 0

12.5% of strontium-90 would remain in a sample after three half-lives have passed. Half-life automatically means 50% of the original amount would remain.

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Which of the following statements are true of thermal energy and kinetic
Karolina [17]

Answer:

A. All the molecules or atoms in motion have kinetic energy.

B. All the molecules or atoms in motion have thermal energy.

C. Each molecule or atom in motion has thermal energy.

D. Each molecule or atom in motion has kinetic energy.

Explanation:

6 0
2 years ago
When 1.82 mole of HCL reacts with excess MnO2, how many moles of Cl2 form?
liubo4ka [24]
The balanced reaction is:

MnO2<span>(s) + 4HCl(aq) → Cl2(g) + MnCl2(aq) + 2H2O(l)
</span>
We are given the amount of hydrochloric acid to be used for the reaction. This will be the starting point for the calculations.

1.82 mol HCl ( 1 mol Cl2 / 4 mol HCl) = 0.46 mol Cl2

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6 0
3 years ago
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6 0
3 years ago
Most acid precipitation results from the combination of _____ with water in the atmosphere, forming strong acids that fall with
aleksley [76]

Answer:

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Explanation:

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Examples:

                                 SO₂  +  H₂O     →     H₂SO₄

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From above examples it can be seen that the sulfur and nitrogen oxides when reacted with water forms strong acids. These acids come along with rain water and causes different problems to living organisms and non living objects like buildings.

4 0
3 years ago
If you have 1.29 moles of NaCl in 4 liters of solution, what is the molarity of the solution?
Illusion [34]

Answer:

0.32M

Explanation:

Given parameters:

Number of moles of NaCl  = 1.29moles

Volume of solution = 4liters  = 4dm³

Unknown:

Molarity of solution = ?

Solution:

Molarity is one the ways of expressing the concentration of a solute in a solution. It is given as;

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7 0
3 years ago
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