Bài 21. Tính theo công thức hóa học

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


Lê Ngọc Diễm
Lê Ngọc Diễm
Trêng THCS Phó Ch©u tr©n träng kÝnh chµo quý thÇy, c« ®Õn dù tiÕt häc
Trêng THCS Phó Ch©u tr©n träng kÝnh chµo quý thÇy, c« ®Õn dù tiÕt häc
!
!


 !"#
 !"#


$%&'()
$%&'()
*+
*+
,-( .&*ế
,-( .&*ế
phân Ure
phân Ure
/,
/,
0
0
1

1
0
0
234
234
('56'789
('56'789
2.
2.
Hãy cho biết khí Oxi nặng hay nhẹ hơn khí Hidro
Hãy cho biết khí Oxi nặng hay nhẹ hơn khí Hidro
bao nhiêu lần?
bao nhiêu lần?
.&*/,
0
1
0
23có
2 mol N
2 mol N
4 mol H
4 mol H
1 mol C
1 mol C
Khí oxi nặng hơn khí hidro là:
Khí oxi nặng hơn khí hidro là:
16 lần
16 lần
1 mol O
1 mol O

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
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$
%&'()*
%&'()*
+,-$./0
+,-$./0
123
123
4
4
5 
5 

 65$7#-89!"#
 65$7#-89!"#
= 39 + 14 + (16 x 3 ) = 101 (g) M
KNO
3
&$: $-123
4

1
;:6 $-9
2
;:6 $-9
<
3
;46 $-9
& !"#$
& !"#$
*
*


%K =
39 x 100%
101
= 38,6%
%N =
14 x 100%
101
= 13,8%
%O =100% -(38,6 +13,8)%= 47,6%

%=08>*
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
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 C!"#$
: $-
?&@ 
 5$A8BC
 C!"#
%O =
3 x 16 x 100%
101
= 47.6%
D$E*


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
 !"#$
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%
%

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.DE
.DE
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4*F
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,-=  &G>
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A8BC6'23&C 
H23
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,-=  &G>
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A8BC6'8I>3
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3
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#
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2(B:
4*F
4*F
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<: $-!"B3
.  &G6'
8&C H
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?&@ A# $-!"B C
!"#$: $-
?&@  5$
7-8 C!"#

M
CuO
= 64 + 16 = 80 ( g)
%Cu =
64 x 100%
80
= 80%
%O =
16 x 100%
80
= 20%


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.=>?4'@






 !"#$
 !"#$
%
%
&'()*
&'()*
%=08>*

?&@ 7#-8 $-
?&@ A# $-!"B C
!"#$: $-
?&@  >
A8BC C!"#
40#
40#
+
F5
G
3
4

;HIGJ:I4;:IK69
&$: $-F5
G
3
4
G $-F5<4 $-3
& !"#
$
%Fe=
2 x 56 x 100%
160
= 70%
%O =
3 x 16 x 100%
160
= 30%
D$E

%O = 100% - 70% = 30%
% A =
x.M
A
M
A
x
B
y
x 100%
% B =
y.M
B
M
A
x
B
y
x 100%
:'4?6'C H
:'4?6'C H
"
"
J
J
<
<



Em hãy tính xem:
Em hãy tính xem:
.
.
 &G6'
 &G6'
823&!'C 
823&!'C 
H234(K
H234(K
 &G6'
 &G6'
823&*C 
823&*C 
H23A9
H23A9


.:#;<0*
.:#;<0*
.=>?4'@
.=>?4'@






 !"#$

 !"#$


2(B:
:'4?6'C H"
:'4?6'C H"
J
J
<
<


% A =
% A =


x.M
A
M
M
A
A
x
x
B
B
y
y
x 100%
x 100%

% B =
% B =
y.M
y.M
B
B
M
M
A
A
x
x
B
B
y
y
x 100%
x 100%
?&@ 7#-8 $-
?&@ A# $-!"B C!"#$
: $-
?&@  
>A8BC
>A8BC
 C!"#
&$: $-=!3: $-!"
&$: $-=!3: $-!"
B=!<: $-!"B3
B=!<: $-!"B3
LM$K: $-=!3K: $-

LM$K: $-=!3K: $-
!"B=!<K: $-!"B3
!"B=!<K: $-!"B3
m
m
Cu
Cu
= 0,1 x 64 =6,4 (g)
= 0,1 x 64 =6,4 (g)
<
<
m
m
O
O
= 0,1 x 16 = 1,6 (g)
= 0,1 x 16 = 1,6 (g)
L 
L 


=!3
=!3
M
M
N
N
NK
NK
M

M
K:6 $-9
K:6 $-9
O=!
O=!
;
;
IP
IP
N
N
:KKO
:KKO
;
;
NKO
NKO
O3
O3
;
;
:I
:I
N
N
:KKO
:KKO
;
;
GKO

GKO
2! Q
2! Q








% B
% B
=
=
m
m
B
B
a
a
x 100%
x 100%
% A
% A
=
=
m
m
A

A
a
a
x 100%
x 100%
,N
,N
%O = 100% - 80% = 20%


.:#;<0*
.:#;<0*
.=>?4'@
.=>?4'@




 !"#$
 !"#$


2(B:
:'4?6'C H"
:'4?6'C H"
J
J
<
<



% A =
% A =


x.M
A
M
M
A
A
x
x
B
B
y
y
x 100%
x 100%
% B =
% B =
y.M
y.M
B
B
M
M
A
A
x

x
B
B
y
y
x 100%
x 100%
?&@ 7#-8 $-
?&@ A# $-!"B C!"#$
: $-
?&@  5$7#-8
 C!"#
:'4''C H"
:'4''C H"
J
J
<
<




% B
% B
=
=
m
m
B
B

a
a
x 100%
x 100%
% A
% A
=
=
m
m
A
A
a
a
x 100%
x 100%
OM()
M:*
M:*


&@  65$
7#-89!"#
$R3
G

&@  
&@  
!"#F5<3$4G
!"#F5<3$4G

F5
F5
G
G
3
3
4
4


MG*
MG*


M4*
M4*
= S!/. A!*
62D
P
9
G
R3
P
2D
P
23
4
62D
G
9

G
=3
+S!/. $ -82
->T
A: (NH
4
)
2
SO
4

B: NH
4
NO
3

C: (NH
2
)
2
CO
2


.&PQ: R?
&@  65$7#-89
!"#$$UA!
CTHH
&O!"#$
CO %C = % O =

Fe
3
O
4
%Fe = %O =
SO
3
%S = %O =
PGVO
WGPO
PKO
HW:O
GWIO
IKO


.:0*<0*
.:0*<0*
.=>?4'@
.=>?4'@




 !"#$
 !"#$
2(B:
S.TA8BC6'C H
S.TR856'78
&*C H+

S.T  &G>A8BC
6'78&C H
2!
2!
-Q
-Q








% A =
x.M
A
M
M
A
A
x
x
B
B
y
y
x 100%
x 100%
% B =

% B =
y.M
y.M
B
B
M
M
A
A
x
x
B
B
y
y
x 100%
x 100%
2! 
2! 
Q
Q






% A =
m
A

a
x 100%
% B =
m
B
a
x 100%


Hướng dẫn học ở nhà
?D!,08>7' 
<' 5$7#-8
!"#$
?X 0MA#:<A#46W:9
?Y8> )Z!"#
[


.:@A:UV
/\ ]^


SMILE ALWAYS