Chemical Equations Review

A chemical equation is balanced when the:

• coefficients of the reactants equal the coefficients of the products.

• same number of each kind of atom appears in the reactants and in the products.

• products and reactants are the same chemicals.

• subscripts of the reactants equal the subscripts of the products.

Tags

NGSS.MS-PS1-5

What type of reaction is shown in the equation below? 2H₂O → 2H₂ + O₂

• synthesis

• decomposition

• single replacement

• double replacement

Which chemical reaction supports the law of conservation of matter?

• K + MgBr → KBr + Mg

• 2K + 2MgBr → K₂Br + 2Mg

• K + 2MgBr → KBr + 2Mg

• 2K + MgBr → 2KBr + Mg

Tags

NGSS.MS-PS1-5

Look at the following equation. Au2O3 → Au + O2 In order to follow the law of conservation of mass, this equation must have which set of coefficients, in order from left to right?

• 2, 4, 3

• 1, 3, 1

• 2, 1, 3

• 1, 1, 3

Tags

NGSS.MS-PS1-5

Chemical equations must be balanced because

• the mass of the reactants is always greater than the mass of the products.

• the mass of the products is always greater than the mass of the reactants.

• mass can neither be created nor destroyed.

• mass is determined by a chemical reaction.

Tags

NGSS.MS-PS1-5

Look at the following equation. Fe + Cl2 → FeCl3 In order to follow the law of conservation of mass, this equation must have which set of coefficients, in order from left to right?

• 3, 1, 2

• 2, 1, 3

• 2, 3, 2

• 1, 3, 1

Tags

NGSS.MS-PS1-5

What type of reaction is displayed below? AgNO3 + KI → KNO3 + AgI

• synthesis

• decomposition

• single replacement

• double replacement

A chemical equation is shown. 8AgS → 10Ag + S₈ Which statement BEST describes the chemical equation?

• It is balanced because the products contain the same number of sulfur (S) atoms as the reactants.

• It is unbalanced because the products contain fewer silver (Ag) atoms than the reactants.

• It is balanced because the mass of the reactants is equal to the mass of the products.

• It is unbalanced because the number of reactants is less than the number of products.

Tags

NGSS.MS-PS1-5

Chemical equations should be balanced so that they demonstrate the law of conservation of mass. Which of the following statements about balanced chemical equations is correct?

• The products must contain the same numbers and types of atoms as the reactants.

• The products must contain the same arrangement of atoms as found in the reactants.

• The products must contain the same numbers but not the same types of atoms as the reactants.

• The products must contain the same types but not the same numbers of atoms as the reactants.

Tags

NGSS.MS-PS1-5

When balancing a chemical equation, which of the following can be changed?

• the coefficients

• the subscripts

• the formulas

• the mass