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2 years ago

A substance was analysed and was found to have a boiling point of 450 °C.

Chemistry

1 answer:

Oksi-84 [34.3K]2 years ago

7 0

Answer:

D: 142 °C

Explanation:

In pure substances, melting and boiling points are usually two distinct temperatures.

They are -12°C and 142°C.

We are told that at room temperature, thus substance becomes a soft grey solid. Thus, we can say that the temperature of the melting point is 142°C.

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What is the maximum number of grams of ammonia, nh3, which can be obtained from the reaction of 10.0 g of h2 and 80.0 g of n2? n

Lelechka [254]

Answer: The mass of ammonia produced is 28.22 g

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For hydrogen gas:

Given mass of hydrogen gas = 10.0 g

Molar mass of hydrogen gas = 2 g/mol

Putting values in equation 1, we get:

$\text{Moles of hydrogen gas}=\frac{10.0g}{2g/mol}=5mol$

For nitrogen gas:

Given mass of nitrogen gas = 80.0 g

Molar mass of nitrogen gas = 28 g/mol

Putting values in equation 1, we get:

$\text{Moles of nitrogen gas}=\frac{80.0g}{28g/mol}=2.86mol$

The given chemical equation follows:

$N_2+3H_2\rightarrow 2NH_3$

By Stoichiometry of the reaction:

3 moles of hydrogen gas reacts with 1 mole of nitrogen gas

So, 5 moles of hydrogen gas will react with = $\frac{1}{3}\times 5=1.66mol$ of nitrogen gas

As, given amount of nitrogen gas is more than the required amount. So, it is considered as an excess reagent.

Thus, hydrogen gas is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

3 moles of hydrogen gas produces 1 mole of ammonia

So, 5 moles of hydrogen gas will produce = $\frac{1}{3}\times 5=1.66moles$ of ammonia

Now, calculating the mass of ammonia from equation 1, we get:

Molar mass of ammonia = 17 g/mol

Moles of ammonia = 1.66 moles

Putting values in equation 1, we get:

$1.66mol=\frac{\text{Mass of ammonia}}{17g/mol}\\\\\text{Mass of ammonia}=(1.66mol\times 17g/mol)=28.22g$

Hence, the mass of ammonia produced is 28.22 g

4 0

2 years ago

At 1 atm, how many moles of co2 are released by raising the temperature of 1 liter of water from 20∘c to 25∘c? express your answ

tekilochka [14]

Answer is: 0,0030 mol of carbon dioxide.
Carbon dioxide solubility in water at 20°C and 1 atm is: 3,8·10⁻² mol/L.
Carbon dioxide solubility in water at 25°C and 1 atm is: 3,5·10⁻² mol/L.
Difference is: 0,038 mol/L - 0,035 mol/L = 0,003 mol/L.
V(carbon dioxide) = 1 L.
n(carbon dioxide) = V · c.
n(carbon dioxide) = 1 L · 0,003 mo/L.
n(carbon dioxide) = 0,0030 mol.

4 0

2 years ago

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Witch of the following isotopes would most likely be unstable and therefore radioactive?

STALIN [3.7K]

The answer is D; Mercury-194
All of the others are not when I looked them up

5 0

2 years ago

Why does silver iodide have a higher melting point than vanillin

MAVERICK [17]

AgI has a higher melting point than vanillin because it is an ionic compound. The bonds are held more tightly together than in vanillin because it is a covalent compound. Ionic bonds have a higher melting point because the electrons are being transferred from one atom to the other.

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2 years ago

The combustion of propane (c3h8) produces co2 and h2o: c3h8 (g) + 5o2 (g) → 3co2 (g) + 4h2o (g) the reaction of 2.5 mol of o2 wi

Andrews [41]

The answer is 2 mol of H₂O will be produced.
The balanced equation for the chemical reaction is:

c3h8 (g) + 5o2 (g) → 3co2 (g) + 4h2o (g)
5 moles of O₂ produces 4 moles of H₂O, and when there is 2.5 mol of O₂, moles of H₂O will be:
2.5 x 4/5 = 2 mol of H₂O

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2 years ago