Chemical reactions Test Review

A bread bag says “This product baked using a mold inhibitor” means All natural ingredients An ingredient that encourages the rising of yeast An ingredient that helps prevent the growth of mold Several different types of preservatives

Which of these is NOT evidence of a chemical reaction? An iron nail changes to a brownish-orange color An ice cube melts into liquid water An antacid tablet produces bubbles of gas when placed in water A piece of zinc raises the temperature of an acid as it reacts

According to the law of conservation of mass, how does the mass of the products in a chemical reaction compare with the mass of the reactants? The mass of the products is greater The mass of the reactants is greater There is no relationship The masses are equal

A shorthand method of writing a chemical reaction is a Synthesis reaction Coefficient Chemical equation catalyst

According to the law of conservation of mass, if two atoms of hydrogen are used as a reactant, how many atoms of hydrogen must be part of the product? 2 1 4

What is the solid called that separates out during a specific type of a reaction? A precipitate An inhibitor A coefficient A catalyst

The symbol  mean _____. And Aqueous Yields reactants

Which of these is a reason a catalyst is added to a chemical reaction? To stabilize a substance To speed up a reaction To produce a greater amount of the catalyst To prevent a compound from forming

Which of these is a product for the reaction shown below Pb(NO3)2 + 2Kl  Pbl2 + 2KNO3 PbI2 Pb KI

A scientist is studying a chemical reaction in which iron (Fe) and sulfur (S) react to produce iron sulfide (FeS). Which of these chemical equations correctly represents this reaction? FeS  Fe + S Fe + S  FeS FeS + S  Fe Fe + FeS  S

CaCO3  CaO + CO2 How much of CO2 is produced from the decomposition of 350g and CaCO3 if 114g of CaO are produced? CaCO3  CaO + CO2 350g  114g + x -114g -114g 236g = x

A new substance was created When silver coins are found in ancient shipwrecks, they are coated with a black crust. How would you know that a chemical change (and not physical change) caused the black crust to form? A new substance was created

What do balanced chemical equations have to do with the law of conservation of mass? A mass is the same before and after the chemical reaction. Each element has the same number of atoms on each side of the equation.

Exothermic – releases energy and heat To develop a product that warms people’s hands, would you choose an exothermic or endothermic reaction to use? Why? Exothermic – releases energy and heat

Explain why the sum of the coefficients on the reactant side of a balanced equation does not have to equal the sum of the coefficients on the product side of the equation. Not every element gets a coefficient depends on the compounds that are created in the products