Question

Barium reacts with H2O to produce hydrogen.

(a) Write a balanced chemical equation for the reaction, using the smallest integer coefficients possible. Write states in brackets. (Hint: Ba(OH)2 is the second product.) in the parenthesis label state also: aq, s , l , g

________ ( ) + _________( ) ------> ________( ) + ________( )

(b) Calculate the mass of pure Ba that will furnish 8.23 L of hydrogen at a pressure of 0.706 atm and a temperature of 26.6°C.

________g

Answer 1

a) the balanced equation is as follows

Ba(s) + 2H2O (l) -----------------------> Ba(OH)2 (aq) + H2 (g)

Ba(OH)2 is slightly soluble in water

b) volume = 8.23 L

pressure = 0.706 atm

temperature = 26.6c = 299.6 Kelvin

gas constant R = 0.0821 L atm / mol k

using the ideal gas equation PV = nRT

n = PV / RT

n = 0.706 * 8.23 / 0.0821 * 299.6 = 0.2362 moles

from the equation

1 mole Ba --------------------------> 1 mole H2

? ------------------------------------> 0.2362 moles

=> 0.2362 moles of Ba

mass of Ba = moles * molar mass = 0.2362 * 137.327 = 32.44 grams