Question

1. Consider the unbalanced equation:

Answer 1

Answer:

1.) 17.76 moles H₂O

2.) 323.1 g HCN

Explanation:

1.) An equation is balanced when there is an equal amount of each element on both sides of the reaction. The quantities can be modified by adding coefficients in front of the molecules.

The unbalanced equation:

Al₄C₃(s) + H₂O -----> Al(OH)₃(s) + CH₄(g)

Reactants: 4 aluminum, 3 carbon, 2 hydrogen, 1 oxygen

Products: 1 aluminum, 1 carbon, 7 hydrogen, 3 oxygen

The balanced equation:

Al₄C₃(s) + 12 H₂O -----> 4 Al(OH)₃(s) + 3 CH₄(g)

Reactants: 4 aluminum, 3 carbon, 24 hydrogen, 12 oxygen

Products: 4 aluminum, 3 carbon, 24 hydrogen, 12 oxygen

Now that the equation is balanced, you can use the relevant coefficients to construct a mole-to-mole ratio. This will allow you to convert between moles Al₄C₃ to moles H₂O.

 1.48 moles Al₄C₃           12 moles H₂O
----------------------------  x  ------------------------  =  17.76 moles H₂O
                                         1 mole Al₄C₃

2.) To find the mass of HCN, you need to (1) convert grams NH₃ to moles NH₃ (via molar mass), then (2) convert moles NH₃ to moles HCN (via mole-to-mole from equation coefficients), and then (3) convert moles HCN to grams HCN (via molar mass). It is important to arrange the coefficients in a way that allows for the cancellation of units.

Molar Mass (NH₃): 14.009 g/mol + 3(1.008 g/mol)

Molar Mass (NH₃): 17.033 g/mol

Molar Mass (HCN): 1.008 g/mol + 12.011 g/mol + 14.009 g/mol

Molar Mass (HCN): 27.028 g/mol

2 CH₄(g) + 3 O₂(g) + 2 NH₃(g)  ------> 2 HCN(g) + 6 H₂O(g)

203.6 g NH₃            1 mole            2 moles HCN           27.028 g
---------------------  x  ----------------  x  ------------------------  x  -----------------  =
                                17.033 g           2 moles NH₃             1 mole

=  323.1 g HCN