Stoichiometry and Calorimetry

Question 1

what are the greenhouse gases

Answer 1

carbon dioxide, methane and water vapour

Question 2

stoichiometry

Answer 2

the study and calculations of mole ratios of substances involved in chemical reactions

Question 3

chemical equation to calculate volume of gas at SLC

Answer 3

V = n x Vm

Question 4

chemical equation to calculate gas volume at non-SLC

Answer 4

PV = n x T x R

Question 5

worded equation to caculate gas volume at non-SLC

Answer 5

pressure (KPa) x volume (L) = moles x temperature (Kelvins) x gas constant (8.31)

Question 6

calorimetry

Answer 6

the experimental method of measuring the heat energy released or absorbed by a chemical reaction or physical process

Question 7

what occurs in calorimetry

Answer 7

the heat energy released by a chemical reaction is transferred to water in a seperate container, the heat energy raises the temperature of the water, which we can then use to calculate the quantity of heat transferred

Question 8

what is a calorimeter

Answer 8

a thermally insulated container, usually holding water

Question 9

what is teh purpose of insulation around the calorimeter

Answer 9

to prevent heat loss

Question 10

what is the purpose of the stirrer in the calorimeter

Answer 10

ensures the temperature of the water is uniform

Question 11

what are the two types of calorimeters for the different types of reactions

Answer 11

a bomb calorimeter and a solution calorimeter

Question 12

when is a bomb calorimeter used

Answer 12

used to measure the heat of combustion of chemical reactions that involve gaseous reactnat or products (e.g combustion of foods)

Question 13

purpose of a vessel in a calorimeter

Answer 13

can withstand high pressures and is filled with pure oxygen, an electric wire runs through it, delivering electricity to combust the reactant

Question 14

when is a solution calorimeter used

Answer 14

to measure an enthalpy change of a substance dissolved in solution, used to detect whether an exothermic or endothermic reaction has occured

Question 15

what starts the reaction in the solution calorimeter

Answer 15

breaking the glass bulb

Question 16

to create a closed system calorimeter

Answer 16

a lid should be placed on the container, the container of water should be insulated and the container where the food is being combusted should be insulated

Question 17

what is the purpose of calibration in calorimeters

Answer 17

for more accurate measurements of the heat produced in the reaction, by measuring hownmuch energy is required to change the water temp by 1 degrees celcius

Question 18

calibration factor

Answer 18

much energy is required to change the water temp by 1 degrees celcius, given CF

Question 19

chemical equation for energy of electrical calbrilation

Answer 19

E = V x I x t

Question 20

worded equation for energy of elecytrical calibration

Answer 20

energy (joules) = volts x current (amps) x time (secs)

Question 21

chemical equation to calculate CF

Answer 21

CF = E/ ΔT

Question 22

worded equation to calculate CF

Answer 22

calibration factor = energy (joules) / change in temp

Question 23

chemical equation to calculate chemical calbriation

Answer 23

E = n x ΔHc

Question 24

worded equation to calculate chemcial calibration

Answer 24

energy (J) = mols of reactant x heat of combustion

Question 25

why can the temp change not be the difference between the initial and final temp

Answer 25

because the calorimeter is not perfectly insulated si it slowly loses heat during and after the heater is opersating

Question 26

purpose of temp time graph

Answer 26

to establish a more accurate determination of the temperature change