abey_27
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#1
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#1
heyy,

calcium reacts with oxygen to form calcium oxide. What mass of oxygen will react exactly with 60g of calcium?

I know the relative atomic mass of calcium is 40, and oxygen is 16, but how exactly do i use this information to find out what mass of oxygen will react exactly with 60g of calcium?

thanks for your help!
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rainbowbex
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#2
Report 12 years ago
#2
(Original post by abey_27)
heyy,

calcium reacts with oxygen to form calcium oxide. What mass of oxygen will react exactly with 60g of calcium?

I know the relative atomic mass of calcium is 40, and oxygen is 16, but how exactly do i use this information to find out what mass of oxygen will react exactly with 60g of calcium?

thanks for your help!
write an equation for the reaction, O2 + 2Ca ----> 2CaO (I think)

find the moles of calcium in 60g (moles = mass/Mr)

use the equation to find moles of O2 needed (in this reaction the ratio is 1:2 so divide moles of Ca by 2)

use moles of O2 to calculate mass (mass = moles x Mr)

EDIT: ask me to explain anything that didn't make sense
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wer343lit
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#3
Report 12 years ago
#3
2Ca + 02 >>>>>> 2Cao

Moles = Mass/Mr

Moles of Calcium = 60/40 = 1.5

Ratio = 2:1

Moles of O2 = 0.75

Mass = Mr x Moles = 0.75 x 32 = 24g
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Zedd
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#4
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#4
1.0M of CaO = 40g + 16g = 56g

40 / 16 = 2.5

60 / 2.5 = 24

That is how I would figure it out, so you would theoretically need 24g of oxygen to react with 60g of calcium.

EDIT- LOL, I think we'll have confused her with our different methods...
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rainbowbex
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#5
Report 12 years ago
#5
(Original post by Zedd)
1.0M of CaO = 40g + 16g = 56g

40 / 16 = 2.5

60 / 2.5 = 24

That is how I would figure it out, so you would theoretically need 24g of oxygen to react with 60g of calcium.

EDIT- LOL, I think we'll have confused her with our different methods...
Mine and jontys the same.. I just thought best to leave her to actually work it out herself.. yours tho mate.... I don't understannnd!!
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Nren
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#6
Report 12 years ago
#6
o2+2Ca=2cao
the number of moles =given mass in grams divided by the relative mass
u knw that it is o2 +2ca rit so basicall they react wid the ratio 1:1
first u find out how many moles r there in 60 grrams of ca
n=60 divided by 40 =1.5 moles
as i said b4 they react wid 1:1 ratio so
1.5 moles of oxygen will react with 1.5 moles of ca
1.5=x divided by 16=10.6666666667
so 10.6 gms of oxygen is required
hey im sure this is rit so add me to ur frnds list
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wer343lit
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#7
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#7
(Original post by rainbowbex)
Mine and jontys the same.. I just thought best to leave her to actually work it out herself.. yours tho mate.... I don't understannnd!!
I think he worked out the mass of product, so then the mass of reactants must add to give that. Never seen that method before though. :p:
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wer343lit
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#8
Report 12 years ago
#8
(Original post by Nren)
o2+2Ca=2cao
the number of moles =given mass in grams divided by the relative mass
u knw that it is o2 +2ca rit so basicall they react wid the ratio 1:1
first u find out how many moles r there in 60 grrams of ca
n=60 divided by 40 =1.5 moles
as i said b4 they react wid 1:1 ratio so
1.5 moles of oxygen will react with 1.5 moles of ca
1.5=x divided by 16=10.6666666667
so 10.6 gms of oxygen is required
hey im sure this is rit so add me to ur frnds list
It's not a 1:1 ratio. It's 2:1.

2 Ca : O2
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Zedd
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#9
Report 12 years ago
#9
(Original post by Jonty99)
I think he worked out the mass of product, so then the mass of reactants must add to give that. Never seen that method before though. :p:
My boss says I'm special :p: It might be that I've developed a backwards method from my work, I do analysis so I tend to have to work back and find out why something is wrong.
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maisiemets
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#10
Report 3 years ago
#10
(Original post by rainbowbex)
write an equation for the reaction, O2 + 2Ca ----> 2CaO (I think)

find the moles of calcium in 60g (moles = mass/Mr)

use the equation to find moles of O2 needed (in this reaction the ratio is 1:2 so divide moles of Ca by 2)

use moles of O2 to calculate mass (mass = moles x Mr)

EDIT: ask me to explain anything that didn't make sense
with the last step of working out the mass, do i use the relative atomic mass of just calcium of calcium and oxygen added together
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username2889812
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#11
Report 3 years ago
#11
(Original post by wer343lit)
It's not a 1:1 ratio. It's 2:1.

2 Ca : O2
True dat
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username2889812
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#12
Report 3 years ago
#12
(Original post by maisiemets)
with the last step of working out the mass, do i use the relative atomic mass of just calcium of calcium and oxygen added together
while finding mass of O2 , use Mr of O2
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