Law of Conservation Flashcards
the scientific principle that matter is neither created nor destroyed during a chemical change.
Law of Conservation of Mass
a substance that is present at the beginning of a chemical reaction
Reactant
a substance that is produced during a chemical reaction
Product
a number written before a chemical formula to show how many atoms or molecules of that substance are involved in a reaction
Coefficient
a description of a chemical reaction using chemical formulas, subscripts, and coefficients
Chemical Equation
an open system is a system that can freely exchange matter and energy with its surroundings. An open system may appear to violate conservation laws because it can gain or lose matter and energy.
Open System
a system that cannot exchange matter or energy with anything outside it; No outside forces act on a closed system. Closed systems satisfy the law of conservation of energy and the law of conservation of momentum.
Closed System
Which BEST represents a balanced equation?
A. HgO —-> Hg + O2
B. 2Fe + O2 —-> Fe2O3
C. 2H2 + O2 —-> 2H2O
C. 2H2 + O2 —-> 2H2O
A 12 g sample of Mg reacts with 18 g of S. What mass of MgS is MOST LIKELY produced?
A. 6 g
B. 30 g
C. 60 g
D. 216 g
B. 30g
Which is the BEST system to use when studying the law of conservation of mass?
A. A closed system to measure the mass of the reaction
B. An open system to measure the mass of the reaction
C. A large system to give the reaction space to occur
D. A small system to closely observe the reaction
A. A closed system to measure the mass of the reaction
Which are conserved during a chemical reaction?
A. Mass and atoms
B. Volume and mass
C. Atoms and molecules
D. Molecules and volume
A. Mass and atoms
Which BEST describes a chemical reaction applying the law of conservation of mass?
A. An equation which uses energy
B. An equation which does not use energy
C. A balanced equation in which the reactants and products are equal
D. An unbalanced equation in which the reactants and products are unequal
C. A balanced equation in which the reactants and products are equal
If a student is chemically combining 4 g of H with 2 g of O, what will be the mass of the product?
A. 4 g
B. 6 g
C. 8 g
D. 10 g
B. 6 g
A chemical reaction occurs in a sealed test tube. As a result, 24 g of product are produced. Which is MOST LIKELY true?
A. The mass of the reactants was 24 grams
B. The mass of the reactants was less than 24 grams
C. The mass of the reactants was more than 24 grams
D. The mass of the reactants is not related to the 24 g
A. The mass of the reactants was 24 grams
Which products would balance the equation below?
CaCl2 + 2Li —->
A. LiCl + Ca
B. Li2Cl + Ca
C. 2LiCl + Ca
C. 2LiCl + Ca