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Salsk061 [2.6K]

2 years ago

7

The solubility of CaCl2 in water is 25g per 50 mL of H2O. How many grams of CaCl2 will dissolved to form a saturated solution in

10 mL of water?
a. 150g
b. 5g
c. 50g
d. 0.5g

1 answer:

Natasha2012 [34]2 years ago

8 0

Answer: option B. 5g

Explanation:

50mL of H2O dissolves 25g of CaCl2.

Therefore, 10mL of H2O will dissolve Xg of CaCl2 i.e

Xg of CaCl2 = (10 x 25) /50 = 5g

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Answer:

$\boxed{ \text{8.40 g}}$

Explanation:

The half-life of K-40 (1.3 billion years) is the time it takes for half of it to decay.

After one half-life, half (50 %) of the original amount will remain.

After a second half-life, half of that amount (25 %) will remain, and so on.

We can construct a table as follows:

No. of Fraction

<u>half-lives</u> <u> t/yr </u> <u>Remaining</u>

0 0 1

1 1.3 billion ½

2 2.6 ¼

3 3.9 ⅛

We see that after 2 half-lives, ¼ of the original mass remains.

Conversely, if two half-lives have passed, the original mass must have been four times the mass we have now.

Original mass = 4 × 2.10 g = $\boxed{ \text{8.40 g}}$

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2 years ago

Suppose a container holds 1000 hydrogen molecules (H2) and 1000 oxygen molecules (O2) that react to form water. How many water m

mezya [45]

500 water molecules and the remaining 500 O2 molecules. Remember the ratio of H to O in H2O.

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Ethyl alcohol is produced by the fermentation of glucose, C6H12O6. C6H12O6 (s) → 2 C2H5OH (l) + 2 CO2 (g) ΔH° = – 69.1 kJ Given

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Answer:

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Explanation:

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Answer:

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$0.0811 M=\frac{n}{0.0017 L}$

n = 0.0001378 mol

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According to reaction, 2 mol of NaOH neutralize 1 mol of sulfuric acid.

Then 0.0001378 mol of NaOH will neutralize:

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Concentration of sulfuric acid in the acid rain sample is 0.0034467 mol/L.

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2 years ago

Question 2: Phase Changes (14 points) a. Rewrite each of the following equations for phase changes, to include the heat required

lilavasa [31]

Explanation:

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A reaction in which there will be release of heat energy is known as exothermic reaction.

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Hence, phase change from liquid to solid will be exothermic in nature.

Latent heat of fusion is defined as the amount of energy necessary to convert 1 gram of a solid into liquid state at its melting point.

So, when solid state of water changes into liquid state then it means energy is absorbed by the molecules of ice due to which they have gained kinetic energy. Hence, they moved away from each other leading to formation of liquid state of water.

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(ii) The equilibrium reaction equation will be as follows.

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5 0

2 years ago