Lauren.24
Badges: 8
Rep:
?
#1
Report Thread starter 2 years ago
#1
Right, this is a long question because it's in different parts, I get parts a) and b) but I'm stuck on c) ... Please helppp, the answer for c) is 3.2 g but I don't really understand why:
4) A scientist burnt 300 g of metal X in an unsealed beaker .
She then weighed the contents of the beaker and found that it now
weighed 500 g. All of metal X reacted to form a single product, a
metal oxide.
a) Explain why the mass increased
b) Analysis of the metal oxide shows that contains 40% oxygen by mass.
What is the percentage mass of metal X in the oxide?
c) The scientist plans to use the metal oxide as part of a mixture.
The final mixture contains 24% metal X by mass, which all comes from
the metal oxide. What mass of the metal oxide was used to make 8.0 g
of the mixture?
0
reply
charco
Badges: 18
Rep:
?
#2
Report 2 years ago
#2
(Original post by Lauren.24)
Right, this is a long question because it's in different parts, I get parts a) and b) but I'm stuck on c) ... Please helppp, the answer for c) is 3.2 g but I don't really understand why:
4) A scientist burnt 300 g of metal X in an unsealed beaker .
She then weighed the contents of the beaker and found that it now
weighed 500 g. All of metal X reacted to form a single product, a
metal oxide.
a) Explain why the mass increased
b) Analysis of the metal oxide shows that contains 40% oxygen by mass.
What is the percentage mass of metal X in the oxide?
c) The scientist plans to use the metal oxide as part of a mixture.
The final mixture contains 24% metal X by mass, which all comes from
the metal oxide. What mass of the metal oxide was used to make 8.0 g
of the mixture?
You should make some attempt to answer the questions yourself first ...
0
reply
Lauren.24
Badges: 8
Rep:
?
#3
Report Thread starter 2 years ago
#3
(Original post by charco)
You should make some attempt to answer the questions yourself first ...
Hi charco, you don't think I have? Ofc I have! Thanks for the help though.. *sigh*
1
reply
Kameron_16
Badges: 5
Rep:
?
#4
Report 2 years ago
#4
(Original post by Lauren.24)
Right, this is a long question because it's in different parts, I get parts a) and b) but I'm stuck on c) ... Please helppp, the answer for c) is 3.2 g but I don't really understand why:
4) A scientist burnt 300 g of metal X in an unsealed beaker .
She then weighed the contents of the beaker and found that it now
weighed 500 g. All of metal X reacted to form a single product, a
metal oxide.
a) Explain why the mass increased
b) Analysis of the metal oxide shows that contains 40% oxygen by mass.
What is the percentage mass of metal X in the oxide?
c) The scientist plans to use the metal oxide as part of a mixture.
The final mixture contains 24% metal X by mass, which all comes from
the metal oxide. What mass of the metal oxide was used to make 8.0 g
of the mixture?
A) The mass increased because the metal reacted with the oxygen when it was burnt as the beaker was not sealed

B) if 40% of the metal oxide is oxygen then 60% must be metal

C)
24%/60%=0.4 (Find the s.f of percentage that the metal has decreased by)

0.4*40%=16% (Find the new percentage of oxygen using the s.f)

16%+24%=40% (add the percentages to find the total percentage of metal oxide by adding both new percentages for each)

0.4*8 =3.2g (Find 40% of the 8g of the mixture)

Hope this helps!!
1
reply
Lauren.24
Badges: 8
Rep:
?
#5
Report Thread starter 2 years ago
#5
(Original post by Kameron_16)
A) The mass increased because the metal reacted with the oxygen when it was burnt as the beaker was not sealed

B) if 40% of the metal oxide is oxygen then 60% must be metal

C)
24%/60%=0.4 (Find the s.f of percentage that the metal has decreased by)

0.4*40%=16% (Find the new percentage of oxygen using the s.f)

16%+24%=40% (add the percentages to find the total percentage of metal oxide by adding both new percentages for each)

0.4*8 =3.2g (Find 40% of the 8g of the mixture)

Hope this helps!!
Legend, I get it, thank you so muchhh! ☺️
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

How are you feeling now you've started university?

I'm loving it! (57)
14.65%
I'm enjoying it but I'm still settling in (98)
25.19%
I'm a bit unsure (67)
17.22%
I'm finding things difficult (133)
34.19%
Something else (let us know in the thread!) (34)
8.74%

Watched Threads

View All