Answer:
0.00369 moles of HCl react with carbonate.
Explanation:
Number of moles of HCl present initially =
moles = 0.00600 moles
Neutralization reaction (back titration): 
According to above equation, 1 mol of NaOH reacts with 1 mol of 1 mol of HCl.
So, excess number of moles of HCl present = number of NaOH added for back titration =
moles = 0.00231 moles
So, mole of HCl reacts with carbonate = (Number of moles of HCl present initially) - (excess number of moles of HCl present) = (0.00600 - 0.00231) moles = 0.00369 moles
Hence, 0.00369 moles of HCl react with carbonate.
Combustion. You said CH4 'burns' in the question which is another word for combustion.
Answer:
C
Explanation:
Because a compound is TWO or MORE atoms combined together and in C there are two different atoms in answer choice C
PV = nRT
P = 157 kPa = 157 × 10³ Pa
V = 265 ml = 0.265 l
T = 20°C = 293 K
m = 0.479 g
PV•M = mRT
M = (mRT)/(PV)
M = 0.479 g × 8.314 kPa.l/(mol.K) × 293 K / (157 kPa × 0.265 l)
M ≈ 28.04579 g/mol.
Hence, the Molar Mass of Dinitrogen or Nitrogen Gas is 28 g.