Conservation of mass

Question 1

definition of emipirical formula

give an example of this molcular formula c3h6

Answer 1

the simplest whole num ratio of atoms/ions of each element in a substance
CH2

Question 2

how to calculate the relative formula mass of something

Answer 2

add together the formula mass num in periodic table

Question 3

explain the law of conservation of mass

Answer 3

the mass of products in chemical reaction must equal the mass of reactants

Question 4

when might the mass at the end be different to the mass at the start?

Answer 4

unsealed reaction vessel experiment
gas product escapes therefore lose mass can measure it
gas reactant is in air-cant measure its mass
when reacts form part of product becomes contained inside reaction vessel=mass increases

Question 5

formula for measuring num mole from grams
and concentration
what are the units for measuring concentration?How ud you convert 1000cm3 to dm3

Answer 5

num of moles=mass in g/Mr or Ar

concentration=mass of solute/volume of solution
g dm-3
divide the num by 1000

Question 6

What is a mole?

what is avogadros constant how can we use it to find particles?

Answer 6

certain num of particles

6 x 10 (23) x num of moles

Question 7

what terms does the word particle cover?

Answer 7

num of molecules,atoms,ions