Chemical Equations
During combustion, methane yields carbon dioxide and water. The unbalanced equation for this reaction is: CH4 + O2 CO2 + H2O What coefficients are needed in order to balance this equation?
1, 2, 1, 2
The chemical equation below shows the process of forming water. Balance the equation by calculating the coefficients. H2 + O2 = H2O
2, 1, 2
What coefficients must be used to balance the following chemical reaction? KClO3 KCl + O2
2; 2; 3
Potassium (K) combines with magnesium bromide (MgBr2) to form potassium bromide (KBr) and magnesium (Mg) during a chemical reaction. Which of the following shows the balanced chemical equation for this reaction?
2K + MgBr2 2KBr + Mg
Potassium iodide (KI) combines with mercury chloride (HgCl2) to form potassium chloride (KCl) and mercury iodide (HgI2) during a chemical reaction. Which of the following shows the balanced chemical equation for this reaction?
2KI + HgCl2 2KCl + HgI2
Lithium and oxygen react to form lithium oxide. What is the balanced equation for this reaction?
4Li + O2 → 2Li2O
Calcium carbonate can be used medicinally in vitamins as a calcium supplement or as an antacid. It is formed by bubbling carbon dioxide gas (CO2) through a solution of calcium hydroxide, Ca(OH)2. In addition to calcium carbonate (CaCO3), this reaction also produces water (H2O). Which of the following equations shows the correct balanced equation for this reaction?
Ca(OH)2 + CO2 → CaCO3 + H2O
An unbalanced chemical equation is shown below. CH4 + O2 CO2 + H2O Which of the following particle diagrams correctly represents the balanced form of the equation?
D. One the left side of the picture it has a purple ball in the middle of 4 grey. Then it adds 4 green balls. On the right side it has 2 green balls with a grey in the middle. It adds 2 green balls and 4 grey balls. (I hope this makes sense)
According to the law of conservation of mass, the mass of the reactants in a reaction must the mass of the products in a reaction.
be equal to
A sample of copper powder is heated in an evaporating dish using a Bunsen burner. If the mass of the powder in the evaporating dish increases after heating, this indicates that
the copper must have combined with another substance.