Chemistry Ch 5 Chemical Reactions Homework

Which sample contains the largest number of molecules?

100 g of CH4

Sodium fluoride can be produced from the reaction between sodium metal and fluoride gas. Which of the following represents the balanced chemical equation for this reactions?

2 Na(s) + F2(g)= 2 NaF(s)

Which quantity has the greatest mass

2.0 mol of Na2O

What is the mass of 3.4 x 10^20 molecules of ethanol (C2H6O) expressed in milligrams?

26 mg of ethanol

How many iron atoms are in 0.32 mol of Fe 2O3?

3.9 * 10^23 iron atoms

How many moles of sulfur trioxide are formed from 3 moles of oxygen using the given balanced equation?

6 mol of SO3

Beaker A contains 1 mole of iron atoms, and Beaker B contains 1 mole of lead atoms. Which statements concerning these two samples is known with certanity?

Beakers A and B contain an equal number of atoms

Write a balanced chemical equation for the reaction of acetone (C3H6O) with oxygen (O2) to form carbon dioxide (CO2) and water (H2O)

C3H6O + 4 O2 = 3 CO2 +3 H2O

2 Co(NO3)3(aq) + 3 (NH4)2S(aq) = Co2S2(s) + 3 NH4NO3(aq) is properly balance chemical equation

False

A 100-g sample of the compound below contains less than 6.02 x 10^23 molecules

False

A mole of copper atoms has more atoms than a mole of lead atoms

False

Consider the unbalanced chemical equation: NH3 +O2 = NO + H2O. It requires 55.4 g of NH3 to completely react with 156 g of O2

False

In the reaction: (Ni^2+(aq) + Mg(s) = Ni(s) + Mg^2+(aq), two electrons are transferred from Ni^2 to Mg

False

One term in a balanced chemical equation, contains the coefficient 4 in front of the formula Mg3(PO4)2. This term represents that there are 12 Mg atoms, 4 P atoms and 16 O atoms in this term

False

The subscripts in chemical formulas are changed in order to balance a chemical equations

False

To multiply two numbers in scientific notation, multiply the coefficients together and multiply the exponents in the powers of 10

False

When the mass of a substance produced in a reaction must be calculated, first its number of moles is determined using mole rations, and then Avogadro's number is used to convert moles to grams

False

The Greek letter delta may be written over the reaction arrow in a chemical equation to indicate that

Heat is needed for the reaction to occur

Identifty the correct product that would completel the following double displacements reaction: NaOH + HBr = blank + H2O

NaBr

What are the two half reactions that show how many electrons are gained and lost by each species in the reaction: Ni^2+(aq) + Mg(s) = Ni(s) + Mg^2+ 9aq)?

Ni^2+(aq) + 2 e- = Ni(s) and Mg(s) = Mg^2+(aq) +2 e-

A student runs the reaction: LiOH + CO2 = LiHO3. THis reaction consums 45.0g LiOH and produces 72.8 g of LiHCO3. Which statements concerning this reaction is true?

The actual yield of the product is 72.8 g LiHCO3

The chemical reaction: KCIO3(s)-> KCI(s) + O2(g) is not balanced. Balance this equation, then select the statement that best describes the balanced equation.

The balanced equation will have six atoms of oxygen on each side of the equation.

All chemical reactions convert one substance into another

True

In a chemical reaction, the actual yield of a product may be reduced by side reations

True

The actual yield of a product in a chemical reaction should not exceed its theoretical yield

True

In redox reactions, metals tend to undergo oxidation

Truw

The mass of one ethanol (C2H6O) molecule is 7.65 x 10-^23 grams

true