Chemistry Questions and Answers

For an ideal gas PV = nRT

Amount in moles = n

Volume v = 10.5dm3

Pressure P = 6atm

Temperature T = 30°C + 273 = 303k

R, Gas constant = 0.082 atmdm3k-1 mol

Recall from ideal gas equation

pv = nRT

n = \(\frac{RV}{RT}\)

n = \(\frac{6 \times 10.5}{0.082 \times 303}\)

n= 2.536mol

Ethene is produced from cracking which involves breaking up large hydrocarbon molecules into smaller and more useful bits. This is achieved by using high temperatures and pressures without a catalyst.

C₁₅H₃₂ → 2C₂H₄ + C₃H₆ + C₈H₁₄
......Δheat...ethene........propene.........octane

protons = 9

neutrons = 10

electrons = 10

Electronic configuration = 2, 8

Ground state Electronic configuration=2, 7

It means that the atom has gained an electron thereby making it have a negative ion.

When an atom donates an electron, it becomes positively charged.

When an atom accepts an electron, it becomes negatively charged

Bubbling of air through the acid solution removes deposited oxides of nitrogen.

Nitric acid is prepared in the laboratory by heating a nitrate salt with the concentrated acid.
NaNO₃ + H₂SO₄ → NaHSO₄ + HNO₃

Vapours of nitric acid are condensed to a brown liquid in a receiver cooled under cold water. "Dissolved oxides of nitrogen" e.g NO₂ are removed by redistillation or blowing a current of carbondioxide or dry air through the warm acid

Upward delivery works well for hydrogen and ammonia, which are both less densed than air. Sometimes, they are collected over water.