Ask a chemistry calculation question for the second year of junior high school and a chemical calcul

You've written all the equations, and you're good to go.

If you look at the equation, the difference in mass between 1 mol of zn before and after producing 1 mol of hydrogen solution is 65-2 (zn-hydrogen) = 63, and now the mass is increased, so the zn participating in the reaction has.

The second question is that the hydrogen produced is also that.

Verify that it is exactly equal to the before and after mass change.

1) The solution before the reaction is dilute sulfuric acid, and the solution after the reaction is zinc sulfate, which can be calculated by using the mass increase before and after the solution.

Zn + H2SO4 === ZnSO4 + H2 M (increase) M(Zn) 100

It can be solved m(zn)=

2）zn + h2so4 === znso4+ h2↑m(h2)

It can be solved m(h2)=

Let the mass of zinc involved in the reaction be x, and hydrogen y grams will be generated.

65/x=2/y

100+x-y=

Solve the above equation to get x=, y=

1) The relative molecular mass of calcium gluconate is 430

2) The mass ratio of each element in calcium gluconate is c:h:o:ca=144:22:224:40=72:11:112:20

3) The mass of calcium that can be replenished every day is grams.

4) The mass fraction of calcium gluconate in this calcium tablet is:

Relative atomic mass: c=12 h=1 0=16 ca=40, so the relative molecular mass of calcium gluconate is (12*6+1*11+16*7)*2+40=430

The mass ratio of each element is c : h : 0 : ca = 72:11:112:20

The calcium supplemented every day is: total relative mass of calcium Relative molecular weight of calcium gluconate * number of calcium tablets ingested * mass of calcium gluconate contained in each tablet = (40 430) * 2 * grams.

The quality score is:

zn+h2so4==znso4+h2↑

13g x65/13g = 2/x

x=generate h2

Difference method, difference in solid mass before and after reaction ==

h2+cuo==△cu+h2o △m

y80/y = 16/

y = so the mass of copper in the original mixture = =

1)__2_c6h6o+_14__o2=__12_co2+__6__h2o

2)__8_nh3+__3_cl2=__6__nh4cl+__2_n2

3)__1_c2h8n2+__4_o2=__2_co2+__1_n2+_4__h2o

13g of zinc reacts with a sufficient amount of dilute sulfuric acid.

k2so4+ba(oh)2=baso4↓+2kohx

174/233=x/

x=>86%

This pack of stuff is quality passable!

Suppose: The mass of potassium sulfate is x

k2so4+ba(oh)2=baso4↓+2kohx

174/233=x/

x=>86%

This package is of good quality!

The relative molecular mass of zinc gluconate is 455; The mass ratio of each element of glucose is 144:22:224:65

Glucose elemental carbon fraction.

34% according to the equation.

2kmno4====k2mno4+mno2+o2316 32

xx/316=x=

The relative molecular weight of glucose is 180

The mass ratio of glucose elements is c:h:o=6:1:8

C% = 40% in glucose

Solution: Potassium permanganate xg is required

2kmNO4===Heating ===K2mNO4+MNO2+O2 316 32

x316 32

--=---xx=

A: Potassium permanganate is required to produce oxygen.

c12h22o14zn==455

c; h; o; zn =144;22;224;The mass fraction of 65zn: 65 455*100%=

c6h12o6=72+12+96=180

Mass ratio of each element of glucose c; h; o=6; 1;8. Mass fraction of glucose carbon 72 180*100%=40%, let the mass of KMno4 be x.

2kmNO4===Heating ===K2mNO4+MNO2+O2 316 32

x316/32=x/3，2g

So x = 31,6g

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