Question

A piece of sodium metal reacts completely with water as follows: 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g) The hydrogen gas generated is collected over water at 19.0°C. The volume of the gas is 255 mL measured at 0.971 atm. Calculate the number of grams of sodium used in the reaction. (The vapor pressure of water at 19.0°C = 0.0217 atm.)

Answer #1

**pressure of H2 = 0.971 atm - 0.0217 atm**

**pressure of H2 = 0.9493 atm**

**now**

**PV = nRT**

**Volume of H2 (V) = 255 ml = 0.255 L**

**Temperature (T) = 19 + 273 K = 292 K**

**so**

**0.9493 x 0.255 = nH2 x 0.0821 x 292**

**nH2 = 0.01**

**now**

**consider the given reaction**

**2 Na + 2 H2O --> 2 NaOH + H2**

**so**

**we can see that**

**moles of Na = 2 times moles of H2**

**so**

**moles of Na = 2 x 0.01 = 0.02 mol**

**now**

**mass of Na = moles x molar mass**

**mass of Na = 0.02 mol x 23 g/mol**

**mass of Na = 0.46 g**

**so**

**0.46 grams of sodium is required**

A piece of
sodium metal reacts completely with water as follows 2Na(s) +
2H2O(l)+2NaOH(aq)+ H2(g) The hydrogen gas generated is collected
over water at 25.0oC. The volume of the gas is 246 mL measured at
1.00 atm. Calculate the number of grams of sodium used in the
reaction. (Vapor pressure of water at 25°C 0.0313 atm.)

Enter your answer in the provided box.
A piece of sodium metal reacts completely with water as
follows:
2Na(s) + 2H2O(l) → 2NaOH(aq)
+ H2(g)
The hydrogen gas generated is collected over water at 25.0°C. The
volume of the gas is 307 mL measured at 0.975 atm. Calculate the
number of grams of sodium used in the reaction. (The vapor pressure
of water at 25.0°C = 0.0313 atm.)
________________g

Consider the reaction
2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)
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A volume of 201 mL of hydrogen is collected over water; the
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M(s) + H2SO4(aq) → MSO4(aq) + H2(g)
A volume of 205 mL of hydrogen is collected over water; the
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Aluminum reacts with aqueous sodium hydroxide to produce
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2NaOH(aq) + 6H2O(ℓ) 2NaAl(OH)4(aq) + 3H2(g) In an experiment, the
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