Question

7. What will the coefficient be for NaOH in the chemical equation listed below when the equation is balanced? H3PO4 (aq) + NaOH (aq) → NasPO4 (aq) + H20 (1) c) 2 d) 4 How many grams of metallic Na will be needed to produce 25.43 grams of Hz upon reaction with H2O? 2 Na (s) + H20 (1) + NaOH (aq) + H2 (g) a) 578.8 g b) 868.3 g c) 289.4 g d) 45.98 g 9. How many grams of CO2 could be produced from the combustion of 1.26 g of C2H2 in the presence of 3.39 g of O2? C2H2 + 502 + 4CO2+ H20 a) 5.54 g b) 4.58 g ( c) 3.73 g d) 6.30 g c-2 H-2 H-2 0-4 0-5 How many grams of H20 will be produced if 10.00 g of CHe are combusted in the presence of 20.00 g of O2 and the reaction yield is 85.0%? c-z 10. CH4 (g) + O2(g) → CO2(g) +2H20 (1) b) 19.1 g c) 4.79 g a) 9.57g d) 18.02 g (-4

Answer 1

7)

The balanced reaction is:

H3PO4(aq) + 3 NaOH(aq) -> Na3PO4(aq) + H2O (l)

Answer: b

8)

2 Na(s) + 2 H2O(l) -> 2 NaOH(aq) + H2(g)

Molar mass of H2 = 2.016 g/mol

mass of H2 = 25.43 g

mol of H2 = (mass)/(molar mass)

= 25.43/2.016

= 12.61 mol

According to balanced equation

mol of Na formed = (2/1)* moles of H2

= (2/1)*12.61

= 25.23 mol

Molar mass of Na = 22.99 g/mol

mass of Na = number of mol * molar mass

= 25.23*22.99

= 5.8*10^2 g

Answer: a

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