Rates of reaction

Question 1

formula

Answer 1

amount / time

Question 2

examples of rate reactions

Answer 2

• precipitation: mix solutions place on flask observe time to be obscured faster disappear the faster the reaction
• change in mass quicker mass drops faster
• volume of gas given off in time interval, when no more gas reaction finished

Question 3

Investigate the effects of changing the conditions of the production of a gas in the reaction between hydrochloric acid and marble chips

Answer 3

Increase in the surface area of the marble chip, the rate of reaction will increase
This is because more surface area particles of the marble chips will be exposed to the dilute hydrochloric acid so there will be more frequent and successful collisions, increasing the rate of reaction

Question 4

explain the precipitation practical

Answer 4

when thiosulfate and hcl are reacted form yellow sulfur

use amount of time to measure rate

measure fixed amount of sodium thiosulfate and hcl place in water bath and gently heat mix and watch till black mark obsecure

repeat at temperatures keeping conc and volume same

Question 5

what does increasing temperature do

Answer 5

particles will have more kinetic energy than the required activation energy, therefore there will be more frequent and successful collisions per second, increasing the rate of reaction

Question 6

what does increasing surface area to volume ratio do

Answer 6

This is because more surface area of the particles will be exposed to the other reactant, producing a higher number of collisions per second

Question 7

what does increasing concentration do

Answer 7

more reactant particles in a given volume, allowing more frequent and successful collisions per second

Question 8

what are enzymes

Answer 8

which speed up the rate of a reaction without themselves being altered or consumed in the reaction
lowering the activation energy required, hence providing a reaction pathway requiring less energy

Question 9

what are enzymes

Answer 9

biological catalyst

catalysed include respiration, photosynthesis and protein synthesis

Question 10

how is alcohol made

Answer 10

fermentation of sugars occurs in the presence of a biological catalyst, yeast enzymes which catalyse glucose to ethanol carbon dioxide