Question

Phonetics: Choose the word whose underlined part is pronounced differently: 1. A. tooth B. clothing C. bath D. both 2. A. gather B. monthly C. father D. brother 3. A. though B. thank C. through D. thin 4. A. clip B. give C. twice D. stupid 5. A. studio B. documentary C. cute D. stupid

Answer 1

Phonetics: Choose the word whose underlined part is pronounced differently:

1. A. tooth B. clothing C. bath D. both

2. A. gather B. monthly C. father D. brother

3. A. though B. thank C. through D. thin

4. A. clip B. give C. twice D. stupid

5. A. studio B. documentary C. cute D. stupid

Answer 2

a)\(Fe+CuSO4-->Cu+FeSO4\)

b) \(n_{Fe}=\frac{1,96}{56}=0,035\left(mol\right)\)

\(m_{CuSO4}=\frac{100.10}{100}=10\left(g\right)\)

\(n_{CuSO4}=\frac{10}{160}=0,0625\left(mol\right)\)

Do \(0,036>0,0625\Leftrightarrow\) \(n_{Fe}< n_{CuSO4}\)

=> CuSO4 dư.Tính theo n chất hết (Fe)

Chất rắn B là Cu

\(n_{Cu}=n_{Fe}=0,035\left(mol\right)\)

\(m_{Cu}=0,035.64=2,24\left(g\right)\)

c) m dd A =\(m_{Fe}+m_{ddCuSO4}-m_{Cu}=1,96+100-2,24=99,72\left(g\right)\)

dd A là FeSO4 và CuSO4 dư

\(n_{FeSO4}=n_{Fe}=0,035\left(mol\right)\)

\(m_{FeSO4}=0,035.152=5,32\left(g\right)\)

\(C\%_{FeSO4}=\frac{5,32}{99,72}.100\%=5,33\%\)

\(n_{CuSO4}=n_{Fe}=0,035\left(mol\right)\)

\(n_{CuSO4}dư=0,0625-0,035=0,0275\left(mol\right)\)

\(m_{CuSO4}dư=0,0275.160=4,4\left(g\right)\)

\(C\%_{CuSO4}dư=\frac{4,4}{99,72}.100\%=4,41\%\)