need help with a question (1 Viewer)

[atrocityx]

well i've been doing revision for my metals topic cause i have an exam first week?
so yeahhh

when samples of aluminum, tin, zinc and lead were heated in air and completely converted to oxide, the masses of metals increased by 89% for aluminium, 27% for tin, 24.5% for zinc and 7.7% for lead. calculate the mass of oxygen that is combined with 5.00g of each metal ?!

O_O"
im seriously confused with this question and i don't know how to work it out =/
is anyone able to help out ?

 

[randomnessss]

Aluminium:

Mass of aluminium oxide = 189% x 5.00

= 9.45 g
​

Mass of oxygen = 9.45 - 5.00

= 4.45 g
​

 

[atrocityx]

Aluminium:

Mass of aluminium oxide = 189% x 5.00

= 9.45 g
​

Mass of oxygen = 9.45 - 5.00

= 4.45 g
​

oh wow! thanksss
umm could you explain how you got that? O.O

 

[randomnessss]

Mass of aluminium oxide = mass of aluminium + mass of oxygen
Therefore since it says that the masses of the metals increase by a certain percentage, it has gained more mass as a result of reacting and combining with oxygen. Since this is just a percentage, you now need to multiply it by the mass of metal (i.e. it increased in mass). This will give you the mass of aluminium oxide. In order to find the mass of oxygen simply subtract the mass of aluminium from the mass of aluminium oxide (i.e. mass of oxygen = mass of aluminium oxide - mass of aluminium).