topic 5 equations

Question 1

perectnage composition equation

Answer 1

total mass of an element in compound /total mass of compound * 100

Question 2

number of mol

Answer 2

volume in dm3 / 24

Question 3

uncertainty

Answer 3

n.o measurements x uncertainty / reading

x100

Question 4

ways to reduce uncertainty

Answer 4

use more precise equipemnt of manipulate experiemtn so that value would be bigger eg dilue acid for titration

Question 5

systematic error

Answer 5

same everytime you repeat experiement due to set up

Question 6

random error

Answer 6

makes results a little bit different each time you repeat experiment

Question 7

what does repeating experiemtns do

Answer 7

reduces effect of random error

Question 8

percentgae error

Answer 8

true - experimental / true x100

Question 9

why is actual yield less than theoretical yield

Answer 9

loss of chemical during pouring or filtering

incomplete combustion
side reactants
reversible reation
impuritites in reactant s

Question 10

what is atom economy

Answer 10

measure of proportion of reactant atoms that become part of desired product

Question 11

ideal gas equation

Answer 11

PV = nRT

p= pascals
v= meters cubed
r =8.31
t= kelvin