a.

\(d_{Zn}=\dfrac{65g\cdot mol^{^{ }-1}}{6,022\times10^{^{ }23}mol^{^{ }-1}\times\dfrac{4}{3}\pi\left(1,38\times10^{-8}\right)^3cm^3}=9,0850\left(g\cdot cm^{-3}\right)\)

b.

\(d_0=0,725d_{Zn}=6,5866\left(g\cdot cm^{^{ }-3}\right)\)

\(1,+n_{fe}=\dfrac{5,6}{56}=0,1\left(mol\right)\)

số nguyên tử của Fe là 0,1.6.10\(^{23}\)=0,6.10\(^{23}\)

=> số nguyên tử của Zn là 3.0,6.10\(^{23}\)=1,8.10\(^{23}\)

+ n\(_{zn}\)= \(\dfrac{1,8.10^{23}}{6.10^{23}}\)=0,3 mol 

=> m \(_{Zn}\)=0,3.65=19,5g ( đpcm)

a) Ta có:

\(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)

Số nguyên tử Zn:

\(0,2.6.10^{23}=1,2.10^{23}\left(nguyêntử\right)\)

b) Nếu như số nguyên tử Cu bằng số nguyên tử Zn khi số mol của Cu bằng số mol của Zn.

=> \(n_{Cu}=n_{Zn}=0,2\left(mol\right)\)

Khối lượng Cu cần lấy:

\(m_{Cu}=0,2.64=12,8\left(g\right)\)

a, \(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)

\(n_{H_2O}=\dfrac{5,4}{18}=0,3\left(mol\right)\)

\(n_{CO_2}=\dfrac{13,2}{44}=0,3\left(mol\right)\)

b, \(n_{NaCl}=\dfrac{0,6.10^{23}}{6.10^{23}}=0,1\left(mol\right)\)

\(n_{Ca}=\dfrac{12.10^{23}}{6.10^{23}}=2\left(mol\right)\)

1) 

\(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\\ A_{Zn}=0,2.6.10^{23}=12.10^{23}\left(\text{nguyên tử}\right)\)

Để \(A_{Cu}=A_{Zn}\Rightarrow n_{Cu}=n_{Zn}=0,2\left(mol\right)\)

\(\Rightarrow m_{Cu}=0,2.64=12,8\left(g\right)\)

2)

A: SO₃

B: H₂O

C: H₂SO₄

D: Fe

E: FeSO₄

F: CaO

G: H₂ 

K: O₂

\(SO_3+H_2O\rightarrow H_2SO_4\\ Fe+H_2SO_4\rightarrow FeSO_4+H_2\\ 2H_2+O_2\xrightarrow[]{t^o}2H_2O\\ CaO+H_2O\rightarrow Ca\left(OH\right)_2\)

\(m_{Zn}=1,6605.10^{-24}.65=1,079325.10^{-22}\left(g\right)\)

\(m_{Fe}=1,6605.10^{-24}.56=9,2988.10^{-23}\left(g\right)\)

1. 

a, K₂O  +  H₂O --> 2KOH (1:1:2)

b, 2Cu + O₂ --> 2CuO (2:1:2)

c, Al₂(SO₄)₃  + 3BaCl₂ -->  3BaSO₄  +  2AlCl₃ (1:3:3:2)

Bài 2:

\(a,n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\\ n_{H_2O}=\dfrac{5,4}{18}=0,3\left(mol\right)\\ n_{CO_2}=\dfrac{13,2}{44}=0,3\left(mol\right)\\ b,n_{NaCl}=\dfrac{0,6.10^{23}}{6.10^{23}}=0,1\left(mol\right)\\ n_{Ca}=\dfrac{1,2.10^{23}}{6.10^{23}}=0,2\left(mol\right)\)

Bài 3:

\(a,m_{H_2SO_4}=0,5.98=49\left(g\right)\\ m_{NaOH}=0,2.40=8\left(g\right)\\ m_{Ag}=108.0,1=10,8\left(g\right)\\ b,n_{SO_2}=\dfrac{15.10^{23}}{6.10^{23}}=2,5\left(mol\right)\\ m_{SO_2}=64.2,5=160\left(g\right)\)

$m_C = 12\ đvC = 1,9926.10^{-23}(gam)$
$\Rightarrow 1\ đvC = \dfrac{1,9926.10^{-23}}{12} = 1,6605.10^{-24}(gam)$

$m_{Zn} = 65\ đvC = 65.1,6605.10^{-24} = 1,079325.10^{-24}(gam)$

Ta có: PTK_Zn = 65(đvC)

Vậy \(m_{Zn}=1,9926.10^{-23}.65=1,29519.10^{-21}\left(g\right)\)