Fichas
Chemistry iGCSE - Chemical Formulae, Equations, Calculations -2
Fichas del conjunto (21)
- 1—Curve A
Faster reaction at higher temperature
Therefore curve is steeper / curve levels off sooner - 2—Curve C
Only half the mass/amount of zinc used
therefore only half the volume / 20 cm3 of hydrogen produced
- 3—0.53 / 106
0.005(0) (mol)
- 4—
- 5—the bung was not replaced quickly after the acid was added (so some carbon dioxide escaped)
some carbon dioxide dissolved in the water in the acid
sodium carbonate is not pure
- 6—funnel (tap)
flask (conical)
jar (gas)
- 7—limewater goes milky / chalky / cloudy
mixture goes clear OWTTE (eg. cloudiness disappears)
- 8—more dense than air/oxygen
- 9—weakly acidic
- 10amount of magnesium = ...... mol0.096 / 24
0.004(0)
- 11amount of HCl = ...... mol0.01(00)
- 12—0.004 mol of Mg react with 0.008 mol of HCI
- 13The reactant in excess is .....HCI is in excess
Mark cq on answers a, i and air
- 14—
- 15—
- 16—as the (hydrochloric) acid/HCl is added
- 17—timer started too late / stopped too early OR
thermometer (scale) read incorrectly / timer read incorrectly
- 18—19.5 (s)
- 19—times are (very) short
heat loss greater
- 20—more collisions / particles have energy equal to / greater than the activation energy
(therefore there are) more successful collisions (per second)
- 21—Any three from
* concentration of the (hydrochloric/nitric) acid
* volume of the (hydrochloric/nitric) acid
* volume of sodium thiosulfate
* temperature