14 A 5-g sample of impure magnesium carbonate is reacted with an excess of hydrochloric acid:
MgCO2 (s) + 2HCl (aq) →
MgCl, (aq) + H, O (1) + CO, (g)
1250 cm of carbon dioxide is collected at rtp.
a How many moles of CO2 are produced?
b What mass of pure magnesium carbonate would
give this volume of carbon dioxide?
(A.: C = 12, O = 16, Mg = 24.)
c Calculate the % purity of the 5-g sample.

Acalorimeter is to be calibrated: 51.203 g of water at 55.2 degree c is added to a calorimeter containing 49.783 g of water at 23.5c. after stirring and waiting for the system to equilibrate, the final temperature reached is 37.6 degree c. specific heat capacity of water (s = 4.18 j/g∙degree c). calculate the calorimeter constant. (smδt)warm water = -[(smδt)cold water + (calorimeterδtcold water)]