Answer:
,
,
,
, 
Explanation:
Empirical formula of the compound is the simplest ratio of elements present in the compound.
Empirical formula of compounds of chlorine with oxygen is as follows:
Compounds in which oxidation state of Cl is +1

Compounds in which oxidation state of Cl is +3

Compounds in which oxidation state of Cl is +4

Compounds in which oxidation state of Cl is +6

Compounds in which oxidation state of Cl is +7

The answer is 33.33 %
The explanation:
According to the reaction equation:
MgCO3(s) + 2HCl (aq) --> MgCl2(aq) + H20(l) + CO2(g)
we can see that 1 mole of MCO3 will produce → 1 mole of CO2
-Now we need o get number of mole of CO2:
and when we have 0.22 g of CO2, so number of mole = mass / molar mass
moles = 0.22 g / 44 g/mol = 0.005 mole
∴ moles of Mg = moles of CO2 = 0.005 mole
∴ mass of Mg = moles * molar mass
= 0.005 * 84 /mol = 0.42 g
∴ Percent of MgCO3 by mass of Mg = 0.42 g / 1.26 * 100
= 33.33 %
From mole ratios, the mass ratio of different elements can be predicted. Also the volume can be predicted based on density for liquids and ideal gas law equation for gases. From the mole ratios, the empirical formula can be predicted, as well as the molecular formula given another data which is mass of the sample.
Answer: A plot of the natural log of the concentration of the reactant as a function of time is linear.
Explanation:
Since it was explicitly stated in the question that the half life is independent of the initial concentration of the reactant then the third option must necessarily be false. Also, the plot of the natural logarithm of the concentration of reactant against time for a first order reaction is linear. In a first order reaction, the half life is independent of the initial concentration of the reactant. Hence the answer.