Question

Chenarele albastre dau și coroana!Am nevoie de ele la școala !clasa a 7 a

Answer 1

1)a) MCaCO₃=40+12+48=1001 mol CaCO₃=100 g
100 g CaCO₃......40gCa.....12gC.......48gO
100 g CaCO₃.........x..............y..............z

x=40%
y=12%
z=48%
b) MCaO=40+12=52
1 mol CaO=52 g
52g CaO.........40gCa.......12gO
100g CaO.........a................b
a=(40*100):52=76,92%C
b=(12*100):52=23,07%O
c)MCH₄=12+4=16
1 mol CH₄=16 g
16g CH₄........12gC...........4gH
100g CH₄.........s.................t
s=(12*100):16=75%C
t=(4*100):16=25%H
d)MMgCl₂=24+35,5*2=24+71=95
1 mol MgCl₂=95 g
95g MgCl₂.........24 g Mg.......71 g Cl
100 g MgCl₂..........q....................r
q=(24*100):95=25,26 % Mg
r=(71*100):95=74,73 % Cl
2)a)36g H₂O
MH₂O=2+16=18 g
18g H₂O..........16g O
36g H₂O.............x
x=(16*36):18=32 g O
b)2 moli H₂SO₄
MH₂SO₄=2+32+64=98
2 moli H₂SO₄=2*98=196 g
98 g H₂SO₄.........64 g O
196 g H₂SO₄..........a
a=(64*196):98=128 g O

c)0,15 kmoli SO₂
MSO₂=32+32=64
n=m/M => m=n*M=0,15*64=9,6 kg
64 kg SO₂...........32 kg O
9,6 kg SO₂.............t
t=(32*9,6):64=4,8 kg O
3)a)MH₂O=2+16=18
18 g H₂O.............2 g H 
   a......................6 g Ha=(18*6):2=36 g H₂O
b)MPH₃=31+3=34
34 g PH₃..................3gH   
b..........................6 gH
b=(34*6):3=68 g PH₃
c)MH₂CO₃=2+12+48=62
62 g H₂CO₃.................2 g H   
    c..........................6 g H
c=(62*6):2=186 g H₂CO₃