Who has the classic junior high school chemistry inference and calculation questions

1) Use carbon monoxide to reduce a gram of iron oxide to obtain grams of carbon dioxide, and find the chemical formula of the oxide.

2) CaCO3 was calcined at high temperature for a period of time, cooled, and the calcium content in the remaining solid was measured, and the mass of Cao in the remaining solid was obtained.

Answer: 1) Let the chemical formula be.

ycoxfe

yco256x+16y

According to the chemical equation, it is calculated that x y=2 3

So the chemical formula is Fe2O3

2) Let the CO2 mass be x and the cao mass be y

x=caoco2

56/y=44/

y=so the mass of cao is.

Solution: Let the mass of hematite be x and the mass of magnetite be y

1). fe2o3+3co=2fe+3co2160 112

70%x 30000t*97%

160/70%x=112/(30000t*97%)x=

2).fe3o4+4co=3fe+4co2232 168

70%y 30000t*97%

232/70%y=168/(30000t*97%)y=

A: --

Solution: Let the mass of hematite be x and the mass of magnetite be yMake a list of reaction equations as follows!

1）fe2o3+3co=2fe+3co2160 112

70%x 30000t*97%

160/70%x=112/(30000t*97%)x=

2).fe3o4+4co=3fe+4co2232 168

70%y 30000t*97%

232/70%y=168/(30000t*97%)y=

Conservation of elements. Let's take x tons of hematite. then x*70%*(112 160)=97%*30000, x=59387 tons; The second question is the same, if you want x tons of magnetite, then x*70%*(168 232)=97%*30000, and the solution is x=57408 tons.

97％*30000=29100t

fe2o3+3co=2fe+3co2

160g* 112g

x 29100tx=29100t

fe3o4+4co=3fe+4co2

232g* 168g

y 29100ty=28130t

A: At least 29,100t hematite and 28,130t magnetite are needed.

1. Set up x tons.

x＊[ 56＊2／(56＊2＋16＊3)]＊70／100＝30000＊97／100

56 2 (56 2 16 3) Calculate the 100% iron content of ferric oxide and multiply it by 70 100 to get the iron content of hematite.

2，x＊[56＊3／(56＊3＋16＊4)]＊70／100＝30000＊97／100

It is planned to produce 30,000* tons of raw tea iron.

1. Set up x tons of hematite x * 112 160 * x = 59,388 tons.

2. Y tons of magnetite ore are required y*168 232*y=57408 tons.

Let's take x tons of hematite. then x 70% (112 160) = 97% 30000, solve x,;

1. a.Mass of oxygen = 10+

b. 2h2o2=(mno2) 2h2o+ o2

m m=2. c.CO2 mass = 25+

cac03 +2hcl = cacl2 + co2 + h2o

m m=20g

d.CaCO3 mass fraction = 20 25 = 80%.

3.2kmNO4 = (heated) K2mMo4 + Mno2 + O2

m m = I wish you progress in your studies!!

rise) for the oxygen mass.

The mass of hydrogen peroxide is x 68 = and the solution is x = g.

rise) carbon dioxide mass is 100+

The mass of CaCO3 involved in the reaction is x 100 =, and the solution is x = 20g, so the mass fraction is 20 25 = 80%.

so the mass of KMNO4 is x (39 + 55 + 64) = and the solution is x =

1. Solution: The mass of oxygen generated is (10+2) grams, and hydrogen peroxide x is used

2H2O2=== (Manganese dioxide catalysis) 2H2O+O2

x then 68 x = 32

Solution x = A: Oxygen is generated.

The hydrogen peroxide participating in the reaction is:

2. The mass of carbon dioxide generated is (25+100).

Let the calcium carbonate participating in the reaction be xg

CaCO3 + 2HCl = == CaCl2 + CO2 (gas) + H2O

xg then 100 xg = 44

The solution yields xg = 20g

Then the mass fraction of calcium carbonate in limestone is 20 25 100% = 80%.

Answer: 3. Oxygen can be produced with x grams of potassium permanganate.

2kmNO4=== (heating) K2mNO4 + MNO2 + O2 (gas).

xg then 316 xg = 32

Get xg = A: omitted.

List the equations that reflect them and answer them one by one.

1a mass of oxygen generated = (10+

b let the mass of H2O2 participating in the reaction be x, according to the chemical equation: 2H2O2 Mno2 2H2O+O2

x can get 68 32 = x ,x= Answer: (omitted) (The above chemical equation is not easy to enter, please forgive me.) ）

2 The mass in the beaker decreases due to the formation of carbon dioxide gas, so the mass of carbon dioxide generated = (25+. Let the mass of calcium carbonate in limestone be x, according to the chemical equation: CaCO3+2HCl=CaCl2+H2O+CO2

x gets 100 44 = x and x = 20g

Mass fraction of calcium carbonate in limestone = 20g 25g 100% = 80% A: (omitted).

3. Oxygen can be prepared by potassium permanganate with mass x, according to the chemical equation:

2kmno4 △ k2mno4 + mno2 + o2↑

x gets 316 32 = x , x = A: (omitted).

1. Establish a salt field and use Taihe Zen to summon Yuyang energy to evaporate naturally.

mgcl2 + ca(oh)2 ==mg(oh)2 + cacl2150* x

The solution is x=