Stoichiometry and Calorimetry Flashcards
(27 cards)
what are the greenhouse gases
carbon dioxide, methane and water vapour
stoichiometry
the study and calculations of mole ratios of substances involved in chemical reactions
chemical equation to calculate volume of gas at SLC
V = n x Vm
chemical equation to calculate gas volume at non-SLC
PV = n x T x R
worded equation to caculate gas volume at non-SLC
pressure (KPa) x volume (L) = moles x temperature (Kelvins) x gas constant (8.31)
calorimetry
the experimental method of measuring the heat energy released or absorbed by a chemical reaction or physical process
what occurs in calorimetry
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
what is a calorimeter
a thermally insulated container, usually holding water
what is teh purpose of insulation around the calorimeter
to prevent heat loss
what is the purpose of the stirrer in the calorimeter
ensures the temperature of the water is uniform
what are the two types of calorimeters for the different types of reactions
a bomb calorimeter and a solution calorimeter
when is a bomb calorimeter used
used to measure the heat of combustion of chemical reactions that involve gaseous reactnat or products (e.g combustion of foods)
purpose of a vessel in a calorimeter
can withstand high pressures and is filled with pure oxygen, an electric wire runs through it, delivering electricity to combust the reactant
when is a solution calorimeter used
to measure an enthalpy change of a substance dissolved in solution, used to detect whether an exothermic or endothermic reaction has occured
what starts the reaction in the solution calorimeter
breaking the glass bulb
to create a closed system calorimeter
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
what is the purpose of calibration in calorimeters
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
calibration factor
much energy is required to change the water temp by 1 degrees celcius, given CF
chemical equation for energy of electrical calbrilation
E = V x I x t
worded equation for energy of elecytrical calibration
energy (joules) = volts x current (amps) x time (secs)
chemical equation to calculate CF
CF = E/ ΔT
worded equation to calculate CF
calibration factor = energy (joules) / change in temp
chemical equation to calculate chemical calbriation
E = n x ΔHc
worded equation to calculate chemcial calibration
energy (J) = mols of reactant x heat of combustion
