2 Describing Chemical Reactions

In your own words, describe the purpose of using a chemical equation.

The purpose of using a chemical equation is to keep track of elements and the number of atoms of each of the elements on each side of the equation. Also it is to show substances in a chemical reaction interact. I found this answer watching the instruction. I agree with the instruction.

Identify the number of atoms on the reactant side of the chemical equation. Fe2O3 + 3H2 → 2Fe + 3H2O

There are 2 Fe (iron) atoms. There are 3 O (oxygen) atoms. There are 6 H (hydrogen) atoms.

Nitrogen gas reacts with hydrogen to produce ammonia. Use the chemical equation to complete the statements. N2 + 3H2 → 2NH3

There are 2 nitrogen atoms on the product side. There are 6 hydrogen atoms on the reactant side.

Sample Response: There would have to be three nitrogen atoms in the products. The law of conservation of matter states that the amount of substance before a reaction occurs should be the same as the amount of substance after the reaction. Which facts did you include in your response? Check all that apply.

There are three nitrogen atoms in the products. The law of conservation of mass states that the amount of substance should be the same before and after a reaction.

coefficient

a number that indicates how many times to multiply a variable

chemical equation

a shorthand that uses chemical symbols and molecular formulas to show what occurs during a chemical reaction

Calcium carbonate can break down to form calcium oxide and carbon dioxide. CaCO3 → CaO + CO2 The oxygen atoms on the product side are

balanced because the total number of oxygen atoms is 3.

parts of a chemical equation

Methane and oxygen react to form carbon dioxide and water Reactants Products Plus sign Coefficient

subscript

a letter, number, or symbol that is smaller and just below the normal line of type

law of conservation of mass

a natural law stating that the same amount of mass is present before and after a chemical reaction

The inflation of airbags is due to the breakdown of a single chemical substance into two separate substances. Two molecules of sodium azide (NaN3) break down into sodium (Na) and nitrogen gas (N2) during the reaction. How many sodium (Na) atoms are produced in the reaction?

2 Na atoms

Identify each part of this chemical equation, which describes the burning of methane and oxygen.

A (the entire green box): Chemical Equation B (the blue box): Reactants C (the arrow): Reacts to Form D (the number): Coefficient E (the purple box): Products

Identify each part of this chemical equation, which describes the breakdown of water into hydrogen and oxygen.

A (the entire green box): Chemical Equation B (the blue box): Reactants C (the arrow): Reacts to Form D (the purple box): Products

Sample Response: Chemical equations show how chemicals interact when a reaction occurs. They use symbols and formulas to show the chemical reaction so that chemical names do not need to be written out. They also help keep track of all elements and the number of atoms of each element on each side of the equation. Which facts did you include in your response? Check all that apply.

Chemical equations show how chemicals interact when a reaction occurs. Chemical equations use symbols and formulas to show the chemical reaction so that chemical names do not need to be written out. Chemical equations help keep track of all elements and the number of atoms of each element on each side of the equation.

Use the chemical equation to find the answers. H2CO3 → H2O + CO2

Identify how many oxygen atoms are in the product. 3 Identify how many oxygen atoms are in the reactant. 3

Use the chemical equation to find the answers. BaSO4 + H2SO4 → Ba(HSO4)2

Identify how many oxygen atoms are in the product. 8 Identify how many oxygen atoms are in the reactant. 8

Marcia is given an incomplete chemical equation that includes the number of nitrogen atoms present in the products of the reaction. How can she conclude that the reaction started with three nitrogen atoms?

If the product contains three nitrogen atoms, then the reactant does too. Since the overall mass is conserved in a chemical reaction.

When sugar is burned, water vapor and carbon dioxide are produced. A sugar molecule has a specific number of carbon, hydrogen, and oxygen atoms. Use the balanced chemical equation to identify the number of carbon, hydrogen, and oxygen atoms in sugar. sugar + 12O2 → 11H2O + 12CO2

Sugar has 12 carbon atoms. Sugar has 22 hydrogen atoms. Sugar has 11 oxygen atoms.

Sulfurous acid, H2SO3, breaks down into water (H2O) and sulfur dioxide (SO2). If only one molecule of sulfurous acid was involved in a chemical reaction, how many sulfur (S) atoms would be in the products?

1 atom of sulfur

products

the chemicals present after a chemical reaction occurs

What are the purposes of a chemical equation? Check all that apply.

to show how substances in a chemical reaction interact to shorten the explanation of a chemical reaction to help keep track of atoms in a chemical reaction

The purpose of a chemical equation

to show the substances in a chemical reaction interact to keep track of all elements and number of atoms of each element on each side of the equation