Balancing Chemical Equations

What is the law of conservation of mass?

• Mass can be created or destroyed in a chemical reaction.

• Mass remains constant in a closed system during a chemical reaction.

• Mass can change forms but cannot be created or destroyed.

• Mass is only relevant in physical changes, not chemical reactions.

How many oxygen atoms are present in 2(NH4)3PO4?

• 6

• 7

• 8

• 9

What is the role of subscripts in a chemical formula?

• Subscripts indicate the number of atoms of each element in a molecule.

• Subscripts represent the total mass of the molecule.

• Subscripts show the charge of the molecule.

• Subscripts are used to balance chemical equations.

What is the balanced equation for the reaction of iron(III) chloride and calcium hydroxide?

• 2 FeCl3 + 3 Ca(OH)2 → 2 Fe(OH)3 + 3 CaCl2

• FeCl3 + Ca(OH)2 → Fe(OH)3 + CaCl2

• 3 FeCl3 + 2 Ca(OH)2 → 3 Fe(OH)3 + 2 CaCl2

• FeCl3 + 3 Ca(OH)2 → Fe(OH)3 + 3 CaCl2

Why is it important to balance chemical equations?

• To ensure that the law of conservation of mass is upheld and to accurately represent the quantities of reactants and products.

• To make the equations look more complex and scientific.

• To increase the speed of chemical reactions.

• To reduce the number of reactants needed in a reaction.

How many hydrogen atoms are present in 2(NH4)3PO4?

• 20 hydrogen atoms

• 22 hydrogen atoms

• 24 hydrogen atoms

• 26 hydrogen atoms

How many moles of silver nitrate are needed to react with one mole of copper?

• 1 mole of silver nitrate (AgNO3)

• 2 moles of silver nitrate (AgNO3)

• 3 moles of silver nitrate (AgNO3)

• 4 moles of silver nitrate (AgNO3)

What is the general approach to balancing complex chemical equations?

• Balancing all elements simultaneously without focusing on any specific molecule.

• Balancing one element at a time, starting with the most complex molecule, and adjusting coefficients as necessary.

• Starting with the simplest molecule and working towards the most complex one.

• Only balancing the reactants and ignoring the products.

What is a balanced chemical equation?

• A balanced chemical equation has equal numbers of each type of atom on both sides of the equation, indicating that mass is conserved during a chemical reaction.

• A balanced chemical equation shows the total energy released during a reaction.

• A balanced chemical equation lists all reactants and products without regard to their quantities.

• A balanced chemical equation is one that includes only solid reactants and products.

What is a skeletal equation?

• A chemical equation that shows only the products without reactants.

• A chemical equation that shows the reactants and products but not the coefficients needed to balance it.

• A detailed chemical equation that includes all coefficients and states of matter.

• A simplified version of a chemical equation that omits all reactants.