Đáp án + Giải thích các bước giải:

Câu 29:

$a\big)$

$750ml=0,5l$

$\to C_{M\,KCl}=\frac{1}{0,75}\approx 1,33M$

$b\big)$

$n_{CuSO_4}=\frac{400}{160}=2,5(mol)$

$\to C_{M\,CuSO_4}=\frac{2,5}{4}=0,625M$

$c\big)C_{M\,MgCl_2}=\frac{0,5}{1,5}\approx 0,33M$

$d\big)$

1500ml=1,5l$

$\to C_{M\,Na_2CO_3}=\frac{0,06}{1,5}=0,04M$

Câu 30:

$a\big)$

$500ml=0,5l$

$\to n_{KNO_3}=2.0,5=1(mol)$

$\to m_{KNO_3}=1.101=101(g)$

$b\big)$

$250ml=0,25l$

$\to n_{CaCl_2}=0,25.0,1=0,025(mol)$

$\to m_{CaCl_2}=0,025.111=2,775(g)$

Câu 31:

$a\big)C\%_{KCl}=\frac{20}{600}.100\%\approx 3,33\%$

$b\big)C\%_{K_2SO_4}=\frac{75}{1500}.100\%=5\%$

$c\big)C\%_{NaCl}=\frac{15}{15+45}.100\%=25\%$

$d\big)$

$n_{HCl}=\frac{4,48}{22,4}=0,2(mol)$

$\to C\%_{HCl}=\frac{0,2.36,5}{500}.100\%=1,46\%$

Câu 32:

$a\big)$

$n_{NaCl}=0,9.2,5=2,25(mol)$

$\to m_{NaCl}=2,25.58,5=131,625(g)$

$b\big)$

$250ml=0,25l$

$\to n_{MgSO_4}=0,25.0,1=0,025(mol)$

$\to m_{MgSO_4}=0,025.120=3(g)$

$c\big)m_{MgCl_2}=50.4\%=2(g)$

$d\big)m_{KCl}=200.15\%=30(g)$