Are you ready to take this lesson's quiz? These questions will help you find out. Make sure you understand why each correct answer is correct—if you don't, review that part of the lesson.
What are the coefficients when the equation below is balanced?
\(\_\_\text{Fe}_{(\text{s})} + \_\_\text{O}_{2(\text{g})} \rightarrow \_\_\text{Fe}_{2}\text{O}_{3(\text{s})}\)
- \(1\), \(1\), \(1\)
- \(2\), \(1\), \(1\)
- \(4\), \(3\), \(2\)
- \(10\), \(5\), \(2\)
The law of conservation must apply to both the identity of elements as well as their quantity.
Make a list of elements on both sides of the equation. Multiply the coefficient and subscript to determine the number of atoms of each element. Continue changing the coefficients until the number of atoms of each element are the same on both sides of the equation.
The law of conservation requires there to be the same number of each element on both sides of the equation.
Subscripts belong only to the element right before them, they are never combined.
Write a balanced chemical equation to represent the breakdown of solid calcium hydroxide into solid calcium oxide and water when exposed to heat.
- \(\text{CaOH} \rightarrow \text{CaO} + \text{H}_{2}\text{O}\)
- \(\text{Ca}\text{(OH)}_{2} \rightarrow \text{CaO} + \text{H}_{2}\text{O}\)
- \({\text{Ca(}\text{OH)}}_{2(\text{s})} \rightarrow \text{CaO}_{(\text{s})} + \text{H}_{2}\text{O}_{(\text{l})}\)
- \({\text{Ca(}\text{OH)}}_{2(\text{s})} \rightarrow 2\text{CaO}_{(\text{s})} + \text{H}_{2}\text{O}_{(\text{l})}\)
Chemical formulas are only correct when the charges of the individual ions cancel out. Calcium has a charge of \(2 +\), hydroxide \(1 -\), oxygen \(2 -\) and hydrogen \(1 +\).
When clues are provided, states of matter for compounds should be part of a chemical equation.
The law of conservation requires there to be the same number of each element on both sides of the equation.
Sometimes polyatomic ions are separated in chemical reactions. It can be helpful to write water as \(\text{HOH}\) to visualize the coefficients needed to balance the equation.
Based on this equation, which statement best describes what would be observed as the reaction takes place?
\(\text{Cu}_{(\text{s})} + 4\text{HNO}_{3(\text{aq})} \rightarrow \text{Cu}{(\text{NO}_{3})}_{2(\text{aq})} + 2\text{NO}_{2(\text{g})} + 2\text{H}_{2}\text{O}_{(\text{l})}\)
- Two aqueous solutions are reacting.
- Copper (II) nitrate forms a solid precipitate.
- Bubbles forming from nitrogen dioxide.
- Water and nitrogen dioxide form a precipitate.
The arrow in the equation separates reactants from products.
Look at the symbols that indicate the physical state of the reactants and products.
Gases formed in liquids or solutions produce bubbles.
Precipitates that settle out from mixing two aqueous solutions are always in a solid state.
In this reaction, if the total mass of the reactants sodium and chlorine is \(10.0\text{ g}\), how much of the product can be made?
\(2\text{Na} + \text{Cl}_{2} \rightarrow 2\text{NaCl}\)
- \(5.0\text{ g}\)
- \(10.0\text{ g}\)
- \(20.0\text{ g}\)
- Not enough information to tell
The coefficients are used to balance the number of atoms; there is not enough information provided to be able to apply coefficients to balance mass.
The law of conservation of mass states that the mass of the product must equal the mass of the reactant because matter cannot be created or destroyed.
The coefficients are used to indicate the number of atoms present to balance the equation.
The law of conservation of mass states that the total mass of the product must equal the total mass of the reactant. This is true no matter the physical states or individual amounts of the reactants or products.
What are the coefficients when the equation below is balanced?
\(\_\_\text{C}_{3}\text{H}_{8} + \_\_\text{O}_{2} \rightarrow \_\_\text{CO}_{2} + \_\_ \text{ H}_{2}\text{O}\)
- \(1\), \(1\), \(1\), \(1\)
- \(1\), \(1\), \(1\), \(2\)
- \(1\), \(5\), \(3\), \(4\)
- \(1\), \(5\), \(4\), \(2\)
The law of conservation must apply to both the identity of elements as well as their quantity.
Make a list of elements on both sides of the equation. Multiply the coefficient and subscript to determine the number of atoms of each element. Continue changing the coefficients until the number of atoms of each element are the same on both sides of the equation.
The law of conservation requires there to be the same number of each element on both sides of the equation.
Subscripts in a chemical formula are only distributed to all elements contained in parentheses.
Summary
Questions answered correctly:
Questions answered incorrectly:
