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3 years ago

In order for a substance to change from a liquid to a gas,

Chemistry

1 answer:

Tomtit [17]3 years ago

7 0

Heat must be added in order for a substance to change from a liquid to a gas. This is call vaporization.

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Determine the enthalpy change for the reaction 2C(s) + 2H2O(g) → CH4(g) + CO2(g) using the following:

Sophie [7]

Answer : The enthalpy change for the reaction is, 97.7 kJ

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The given main chemical reaction is,

$2C(s)+3H_2O(g)\rightarrow CH_4(g)+CO_2(g)$ $\Delta H=?$

The intermediate balanced chemical reaction will be,

(1) $C(s)+H_2O(g)\rightarrow CO(g)+H_2(g)$ $\Delta H_1=131.3kJ$

(2) $CO(g)+H_2O(g)\rightarrow CO_2(g)+H_2(g)$ $\Delta H_2=41.2kJ$

(3) $CH_4(g)+H_2O(g)\rightarrow 2H_2(g)+CO(g)$ $\Delta H_3=206.1kJ$

Now we are multiplying reaction 1 by 2 and reversing reaction 3 and then adding all the equations, we get :

(1) $2C(s)+2H_2O(g)\rightarrow 2CO(g)+2H_2(g)$ $\Delta H_1=2\times 131.3kJ=262.6kJ$

(2) $CO(g)+H_2O(g)\rightarrow CO_2(g)+H_2(g)$ $\Delta H_2=41.2kJ$

(3) $2H_2(g)+CO(g)\rightarrow CH_4(g)+H_2O(g)$ $\Delta H_3=-206.1kJ$

The expression for enthalpy of main reaction will be,

$\Delta H=\Delta H_1+\Delta H_2+\Delta H_3$

$\Delta H=(262.6)+(41.2)+(-206.1)$

$\Delta H=97.7kJ$

Therefore, the enthalpy change for the reaction is, 97.7 kJ

3 0

4 years ago

Read 2 more answers

Increasing temperature increases solubility so that 480 grams (g) of sugar makes a saturated solution in 100 milliliters (mL) of

valkas [14]

Solubility at 100 °C = 480 g / 100 mL of solution =: saturated solution

The proportion 240 g / 50 mL is equal to the saturated ratio 480 g / 100 mL

Then, 240 g of sugar in 50 mL of boiling water will make a saturated solution.

Answer: saturated

8 0

3 years ago

How does a difference in 1 pH unit change in terms of H+ concentration? Ex: How does a pH of 3 differ from the pH of 4? Which on

yuradex [85]

Answer:

A difference of 1 would mean there is either x10 more or less depending on where you are starting.

Explanation:

The pH of 3 differs from 4 because the acidity of 3 is 10x higher than that of 4. This is due to how the scientific notation of 3 in relation to pH is 10x^-3 while that of 4 is 10^-4 so in terms of the stronger acid that would be the one with the pH of 3.

6 0

3 years ago

What is the general formula for cycloalkenes.

maria [59]

C( n)H(2n) is the general formula, eg: Cyclohexane is C6H12

3 0

2 years ago

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Plz help me with seven eight and nine

Nookie1986 [14]

7 is atomic symbol 9 is atomic density 8 is the atomic number

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3 years ago