Acetylene Combustion Worksheet PDF

Preview

Summary

Notes...

Description

Name(s):

Combustion of Acetylene Worksheet

/20

Purpose: Learning about complete and incomplete combustion using acetylene as an example. 1. Complete the chart below by name all 4 substances that can be produced in the incomplete combustion of any hydrocarbon and incomplete some of their physical properties. [8] Products of Incomplete Combustion

Chemical formula

Physical properties

Water Carbon dioxide

Odourless, colourless, gas Odourless, colourless, gas

2. (a) When burning a candle, what is the black substance that is formed near the wick? Hint: look at your list of physical properties of the substances in the above table. [1]

(b) Given your answer to question 2a, explain why burning a candle is an example of incomplete combustion. [1]

(c) When burning butane gas in a Bunsen burner, little to no black solids are produced. Based on this statement, what can be concluded about the combustion of butane? [1]

A sample calculation for the complete combustion of butane (C4H10). Study this example to answer the questions below for acetylene. WORD equation:

butane + oxygen  water + carbon dioxide

SKELETON equation:

C4H10 + O2  H2O + CO2

BALANCED equation:

Step 1. Balanced but has a decimal coefficient C4H10 + 6.5 O2  5 H2O + 4 CO2 Step 2. Double all the coefficients to get whole numbers 2 C4H10 + 13 O2  10 H2O + 8 CO2

To determine the theoretical ratio of butane to oxygen needed for complete combustion of butane look at the coefficients of the balanced equation. Butane : oxygen = 2 : 13 To determine the theoretical ratio of butane to AIR needed for complete combustion of butane, you will need to know the proportion of air that is oxygen. Oxygen makes up only 20% or 1/5 of air. Thus you will need 5x the amount of air to get the proper ratio of oxygen to have complete combustion.

Name(s):

3. Given that the chemical formula for acetylene is C2H2, draw the molecular diagram in the space provided. [2] (a) Lewis diagram (recall: unpaired electrons are (b) Structural diagram (recall: a line segment shared in a molecular compound) represents a pair of shared electrons)

4. Write the appropriate equation for the COMPLETE combustion of acetylene. [3] (a) WORD equation:

(b) SKELETON chemical equation:

(c) BALANCED chemical equation (check that you have the lowest common multiple between the coefficients):

5. Based on the balanced equation for the COMPLETE combustion of acetylene (question 4c), theoretically what ratio of acetylene to oxygen gas (O2) is needed? [1]

6. Write the appropriate equation for the INCOMPLETE combustion of acetylene in which all the 3 forms of carbon are produced along with water. [3] (a) WORD equation:

(b) SKELETON chemical equation:

(c) BALANCED chemical equation (check that you have the lowest common multiple between the coefficients):

7. BONUS: If only 20% of the air is oxygen, calculate the theoretical ratio of acetylene to AIR needed for COMPLETE combustion of acetylene. Show your calculations. Hint: You will need to refer to the answer from question 5. [2]...