Question

4. Рассчитайте относительные молекулярные массы соединений: (a) Fe3(PO4)2 (b) Mg(OH)2 (c) H2SiO3 (d) P205​

Answer 1

Mr (Fe3(PO4)2) = 56*3+ 31*2+16*8=358

Mr( Mg(OH)2)=  24+16*2+1*2= 58

Mr(H2SiO3) = 1*2+28+16*3= 78

Mr(P2O5)= 31*2+16*5 =142

Answer 2

Ответ:

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Объяснение:

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Answer 3

Calculating Relative Molecular Masses

(a) Fe3(PO4)2: To calculate the relative molecular mass of Fe3(PO4)2, we need to consider the individual atomic masses of each element and then sum them up according to the molecular formula.

The relative atomic masses are: - Fe (Iron) = 55.85 - P (Phosphorus) = 30.97 - O (Oxygen) = 16.00

Using these values, we can calculate the relative molecular mass of Fe3(PO4)2: \[3 \times \text{Fe} + 2 \times (\text{P} + 4 \times \text{O})\]

\[3 \times 55.85 + 2 \times (30.97 + 4 \times 16.00)\]

\[167.55 + 2 \times (30.97 + 64.00)\]

\[167.55 + 2 \times 94.97\]

\[167.55 + 189.94\]

\[357.49\]

So, the relative molecular mass of Fe3(PO4)2 is 357.49.

(b) Mg(OH)2: The relative atomic masses are: - Mg (Magnesium) = 24.31 - O (Oxygen) = 16.00 - H (Hydrogen) = 1.01

Using these values, we can calculate the relative molecular mass of Mg(OH)2: \[\text{Mg} + 2 \times (\text{O} + 2 \times \text{H})\]

\[24.31 + 2 \times (16.00 + 2 \times 1.01)\]

\[24.31 + 2 \times (16.00 + 2.02)\]

\[24.31 + 2 \times 18.02\]

\[24.31 + 36.04\]

\[60.35\]

So, the relative molecular mass of Mg(OH)2 is 60.35.

(c) H2SiO3: The relative atomic masses are: - H (Hydrogen) = 1.01 - Si (Silicon) = 28.09 - O (Oxygen) = 16.00

Using these values, we can calculate the relative molecular mass of H2SiO3: \[2 \times \text{H} + \text{Si} + 3 \times \text{O}\]

\[2 \times 1.01 + 28.09 + 3 \times 16.00\]

\[2.02 + 28.09 + 48.00\]

\[78.11\]

So, the relative molecular mass of H2SiO3 is 78.11.

(d) P2O5: The relative atomic masses are: - P (Phosphorus) = 30.97 - O (Oxygen) = 16.00

Using these values, we can calculate the relative molecular mass of P2O5: \[2 \times \text{P} + 5 \times \text{O}\]

\[2 \times 30.97 + 5 \times 16.00\]

\[61.94 + 80.00\]

\[141.94\]

So, the relative molecular mass of P2O5 is 141.94.