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3 years ago

What is the pressure of nitrogen in atmospheres of a sample that is at 745 mmHg?

1 answer:

6 0

<span>The pressure of nitrogen in atmospheres of a sample that is at 745 mmHg- n2= .780 atm because 78 (from the 78%) 78/100=0.78.</span>

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When a 0.235-g sample of benzoic acid is combusted in a bomb calorimeter, the temperature rises 1.643 ∘C . When a 0.275-g sample

andrew-mc [135]

Answer : The heat of combustion per mole of caffeine at constant volume is 76197.18 kJ/mole

Explanation :

First we have to calculate the specific heat calorimeter.

Formula used :

$Q=m\times c\times \Delta T$

where,

Q = heat of combustion of benzoic acid = 26.38 kJ/g = 26380 J/g

m = mass of benzoic acid = 0.235 g

c = specific heat of calorimeter = ?

$\Delta T$ = change in temperature = $1.643^oC$

Now put all the given value in the above formula, we get:

$26380J/g=0.235g\times c\times 1.643^oC$

$c=68323.38J/^oC$

Thus, the specific heat of calorimeter is $68323.38J/^oC$

Now we have to calculate the heat of combustion of caffeine.

Formula used :

$Q=c\times \Delta T$

where,

Q = heat of combustion of caffeine = ?

c = specific heat of calorimeter = $68323.38J/^oC$

$\Delta T$ = change in temperature = $1.584^oC$

Now put all the given value in the above formula, we get:

$Q=68323.38J/^oC\times 1.584^oC$

$Q=108224.23J=108.2kJ$

Now we have to calculate the moles of caffeine.

$\text{Moles of caffeine}=\frac{\text{Mass of caffeine}}{\text{Molar mass of caffeine}}$

Mass of caffeine = 0.275 g

Molar mass of caffeine = 194.19 g/mole

$\text{Moles of caffeine}=\frac{0.275g}{194.19g/mole}=0.00142mol$

Now we have to calculate the heat of combustion per mole of caffeine at constant volume.

$\text{Heat of combustion per mole of caffeine}=\frac{108.2kJ}{0.00142mol}=76197.18kJ/mole$

Therefore, the heat of combustion per mole of caffeine at constant volume is 76197.18 kJ/mole

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3 years ago

A(n) ________is your legal document issued by a government that gives an inventor exclusive rights to make use or sell intervent

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Patent - Not sure if this is much of a Chem question dou.

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Identify what the electron dot diagram tells you about bonding

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Which would have a greater impact on the actual mass of a particular soduim atom?

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The protons contribute significantly more to an atom's mass because sodium has an atomic number of 11, where the number of protons in a neutral sodium atom is equal to the number of electrons. In the first group or column of the periodic table, sodium is an alkali metal.

The sodium atom mass has 11 protons and electrons, and its outermost shell has one valence electron. Pure sodium has a high level of reactivity. Since it is such a soft metal, a knife may be used to cut it with ease. The chemical element sodium has the atomic number 11 and the symbol Na.

To learn more about sodium, click here.

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3 natural chemicals a part of our life

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