Chemistry question here...can any one help?

Question

How many tonnes of calcium carbonate must be heated to produce 10 tonnes of calcium oxide. Also, how much CO2 will be released. Please tell me exactly how to do the question- I don't just won't the answer.
Thanks

Answer 1

hints first then solution....

(1) write balanced equation
(2) calculate moles CaCO3 in 10 tonnes
(3) calculate moles CO2 released
(4) calculate mass CO2

solution.....

(1) balanced equation..

calcium carbonate is CaCO3
Calcium oxide is CaO

1 CaCO3 ------> 1 CaO + 1 CO2

this means 1 mole of CaCO3 gives 1 mole CO2

(2) moles CaCO3

moles = mass / molecular weight

mass = 10 tonnes = 10,000 kg = 10^4 kg = 10^7 g
( a tonne is 1000 kg by definition)

molecular weight = 100 g/mole from periodic table so therefore....

moles CaCO3 = 10^7 g / (100 g/mole) = 10^5 moles

(3) moles CO2 released

from the balanced equation in (1), 1 mole CaCO3 gives 1 mole CO2. from (2) we have 10^5 moles CaCO3 so...

10^5 moles CaCO3 x (1 mole CO2 / 1 mole CaCO3) = 10^5 moles CO2

(4) calculate mass CO2

moles = mass / molecular weight
rearranging
mass = moles x molecular weight
moles CO2 = 10^5 from (3)
molecular weight CO2 = 56.1 g/mole from periodic table

so

mass CO2 = 10^5 moles x 56.1 g / mole = 5.6 x 10^6 grams
= 5.6 x 10^3 kg = 5.6 tonnes


**** update ****

hey carpetman. a tonne is 1000 kg. a ton is 2000 lbs.

Answer 2

10 tonnes is 10 million grams. Now divide by 100 (the Mr) to get the moles, which is 100,000.
So 100,000 moles of CO2 are given off, as well as 100,000 moles of CaO. 1 mole of CaO weighs 56g, and 1 mole of CO2 weighs 44g.
So 100,000 moles of each will weigh 5.6 tonnes and 4.4 tonnes respectively.
Note that these two values added together exactly equal the original mass of CaCO3.

Answer 3

caco3---->cao+co2
100ton 56 ton
x 10ton
x=(100*10)/56=1000/56=500/28=250/14=125/7=17.857 ton

Answer 4

First, balance the equation:

CaCO3 ----> CaO + CO2

It is balanced as written.

So, for every one mole of CaCO3 decomposed, 1 mole of CaO will be produced.

Now, let's do the stoichiometry.

10 tons CaCO3 * 2000 lbs/ton * .454 kg/lb * 1 kmol/100 kg CaCO3

= 90.8 kmol

Note: kmol is kilo moles, ie 1000 moles. I wrote it this way to save some time on the math. We convert grams to moles; therefore we can convert kilograms to kilomoles.

So, for every 90.8 kmol of CaCO3, we will produce 90.8 kmol of CaO.

Now convert...

90.8 kmol of CaO * 56 kg/kmol * 1 pound/.454 kg * 1 ton/2000 lbs...

= 5.6 tons of CaO.

I hope this helps.