Help please!! I got a test today on Moles.. 😖

Watch
Aleksander Krol
Badges: 12
Rep:
?
#1
Report Thread starter 1 month ago
#1
In the mark scheme, for Q3 part (a)(v) why did they multiply by 10 x 40. I've seen them using 10x40 in similar questions like this one and idk why :/ i know they are multiplying to get the concentration of ethanol but why 10x40 like where did the 10 and 40 come from? can someone please explain me
Name:  received_589883752007390.jpeg
Views: 9
Size:  52.7 KBName:  received_533035881078424.jpeg
Views: 8
Size:  43.2 KBName:  received_883688135560575.jpeg
Views: 9
Size:  92.7 KB
Last edited by Aleksander Krol; 1 month ago
0
reply
Aleksander Krol
Badges: 12
Rep:
?
#2
Report Thread starter 1 month ago
#2
anyone please 🥺
0
reply
strawberrygemini
Badges: 7
Rep:
?
#3
Report 1 month ago
#3
i think its because concentration has to be moles per dm3 so you have to find out the number of moles in 1000 cm3. They've multiplied it by 10 and 40 to scale up the number of moles to 1000 cm3- beforehand they had worked out the number of moles in 2.5 cm3 (I think), so multiplying it by 10 and 40 finds the number of moles in 1000cm3.
2
reply
username3477548
Badges: 20
Rep:
?
#4
Report 1 month ago
#4
(Original post by strawberrygemini)
i think its because concentration has to be moles per dm3 so you have to find out the number of moles in 1000 cm3. They've multiplied it by 10 and 40 to scale up the number of moles to 1000 cm3- beforehand they had worked out the number of moles in 2.5 cm3 (I think), so multiplying it by 10 and 40 finds the number of moles in 1000cm3.
Yeah this is it
0
reply
Aleksander Krol
Badges: 12
Rep:
?
#5
Report Thread starter 1 month ago
#5
(Original post by strawberrygemini)
i think its because concentration has to be moles per dm3 so you have to find out the number of moles in 1000 cm3. They've multiplied it by 10 and 40 to scale up the number of moles to 1000 cm3- beforehand they had worked out the number of moles in 2.5 cm3 (I think), so multiplying it by 10 and 40 finds the number of moles in 1000cm3.
omg really i appreciate your reply you're a life saver thanks again btw❤️✨
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

Feeling behind at school/college? What is the best thing your teachers could to help you catch up?

Extra compulsory independent learning activities (eg, homework tasks) (18)
7.38%
Run extra compulsory lessons or workshops (37)
15.16%
Focus on making the normal lesson time with them as high quality as possible (44)
18.03%
Focus on making the normal learning resources as high quality/accessible as possible (35)
14.34%
Provide extra optional activities, lessons and/or workshops (63)
25.82%
Assess students, decide who needs extra support and focus on these students (47)
19.26%

Watched Threads

View All