Question

8.99g of scandium and 8.99g of oxygen react to give scandium oxide and a left -over of oxygen 4.19g, what percentage by mass, of scandium oxide is the oxygen
8.99g of scandium and 8.99g of oxygen react to give scandium oxide and a left -over of oxygen 4.19g, what percentage by mass, of scandium oxide is the oxygen

Answer 1

8.99 - 4.19 = 4.8 g oxygen used.
total mass is 8.99 Sc + 4.8 O = 13.79
% O = (4.8/13.79)*100 = ?

Answer 2

m
O
r
e
a
c
t
=
88.9

g
−
4.19

g
=
84.71

g
.

We determine the mass of the product by adding the initial mass of scandium, 88.9 g, and
m
O
r
e
a
c
t
, such that
m
S
c
2
O
3
=
88.9

g
+
84.71

g
=
173.61

g
. We proceed with the solution.

P
=
m
O
r
e
a
c
t
m
S
c
2
O
3
×
100
%
=
84.71

g
173.61

g
×
100
%
≈
48.8
%

O
P
=
m
O
r
e
a
c
t
m
S
c
2
O
3
×100% =
84.71

g
173.61

g
×100% ≈
48.8
%

O