Miscellaneous Flashcards
State the Conservation of Mass in a reaction. (2)
During chemical reactions or a change of state, no atoms are created or destroyed. The total mass of chemicals before and after a reaction remains the same.
How do you write word equations for combustion and incomplete combustion? (2)
Combustion reactions can be described using word equations.
For example, the fuel used in gas barbeques is butane. Butane molecules contain only carbon atoms and hydrogen atoms and it is written as C₄H₁₀.
When the butane burns, the carbon atoms react with oxygen in the air and carbon dioxide, and the hydrogen atoms react with oxygen to make water.
The word equation for the combustion of butane is, butane + oxygen → carbon dioxide + water.
Distinguish between a control (2), independent (1), and dependent (1) variable.
Independent variables – the variable that is being changed during the experiment
Dependent variables – the variable being tested or measured during the experiment
In an experiment, the effect of changing just one variable on another is tested - testing how the independent variable affects the dependent variable. For this reason, other variables must be controlled so that they don’t affect the independent variable. These variables are control variables.
