Chem Homework Questions Unit 4
Lesson 88 pages 447-450... Question 4: Predict the products for the reactions given below. Be sure to balance each equation. g.) 2CH3COOH(aq) + Mg(OH)2 →
(CH3COO)2Mg(aq) + 2H2O(l)
Lesson 88 pages 447-450... Question 1: Describe two ways to make a strong acidic solution safer.
1.) You can dilute it with water 2.) You can neutralize it with s base
Lesson 90 pages 457-460... b.) 2 NaOH(aq) + CaCl2(aq) → Ca(OH)2 (s) +2 NaCl(aq) Write the complete ionic equation:
2Na+(aq) + 2OH-(aq) + Ca+(aq) + 2Cl-(aq) → Ca(OH)2 + 2Na+(aq) + 2Cl-(aq)
Lesson 90 pages 457-460... a.) Hg(NO3)2 (aq) +2 NaCl (aq) → HgCl2 (s) + 2NaNO3(aq) Write the net ionic equation:
2OH-(aq) + Ca+(aq) → Ca(OH)2
Lesson 90 pages 457-460... d.) 3 Zn(NO3)2(aq) + 2 Na3PO4(aq) → Zn3(PO4)2 (s) + 6 NaNO3(aq) Write the net ionic equation:
3 Zn2+(aq) + 2(PO4)3-(aq) → Zn3(PO4)2 (s)
Lesson 90 pages 457-460... d.) 3 Zn(NO3)2(aq) + 2 Na3PO4(aq) → Zn3(PO4)2 (s) + 6 NaNO3(aq) Write the complete ionic equation:
3 Zn2+(aq) + 6NO3-(aq) + 6Na+(aq) + 2(PO4)3-(aq) → Zn3(PO4)2 (s) + 6NO3-(aq) + 6Na+(aq)
Lesson 72 pages 371-374... Question 2: How are the coefficients in chemical equations different from the subscripts in chemical formulas?
A coefficient reflects the number of molecules in a given substance, it is a number placed in front the chemical symbol. A subscript, however, reflects each element's atomic contribution to a given molecule. It is located after the chemical symbol and it is smaller in size and set below the type line.
Lesson 88 pages 447-450... Question 2: What is a neutralization reaction?
A double exchange reaction in which an acid and a base react in aqueous solution to produce an ionic compound (a salt) and water. The pH approaches 7 because the H+ from the acid and the OH- from the base combine to form H2O.
Lesson 69 pages 358-362... Question 3 B: Describe what you think you would observe for these chemical equations. 2H2O2 (aq) → 2H2O(l) + O2(g)
A gas is formed, gas bubbles will appear in the solution
Lesson 70 pages 363-366... Question 1: What is the difference between a physical change and a chemical change?
A physical change occurs when there is only one substance involved and it just changes state, the identity is not changed. A chemical change is when new substances are formed and you know this by seeing that the chemical formula is different on both sides of the equation. The products have properties significantly different form the reactants.
Lesson 69 pages 358-362... Question 3 C: Describe what you think you would observe for these chemical equations. 2NaCl(aq) + Pb(NO3)2(aq) → 2NaNO3(aq) + PbCl2(s)
A solid will form when the two solutions are mixed
Lesson 68 pages 353-357... Question 4: Both bleach and ammonia are used for cleaning. However, it is very dangerous to mix bleach with ammonia because they react to produce sodium hydroxide and the toxic gas chloramine... NaOCl (aq) + NH3 (aq) --> NaOH (aq) + NH2Cl (g) A.) Write an interpretation of the chemical reaction. B.) What do you expect to observe?
A.) Aqueous sodium hypochlorite reacts with aqueous ammonia to produce aqueous sodium hydroxide and chloramine gas. B.) I expect the H and Cl ions to get exchanged, leading to the formation of NaOH. This is a displacement reaction. There is also an evidence of the formation of a gas, NH2Cl (Chloramine gas).
Lesson 68 pages 353-357... Question 5: Poisoning with Mercury Chloride can be reserved by chelation therapy. The chelating agent called EDTA, C10H16N2O8, is injected into the bloodstream. EDTA forms a water-soluble compound with mercury ions, allowing removal from the body through the kidneys. HgCl2 (s) + C10H16N2O8 (aq) -----> HgC10H12N2O8 (aq) + 4HCl (aq) A.) Write an interpretation of the chemical reaction. B.) What do you expect to observe?
A.) Solid Mercury Chloride reacts with aqueous Ethylenediaminetetraacetic acid to produce a solution containing a compound of mercury with Ethylenediaminetetraacetic, and hydrochloric acid. B.) I expect that when the solid Mercury Chloride and Ethylenediaminetetraacetic react, the solid will disappear and a mixture of two liquids remains.
Lesson 90 pages 457-460... Question 3: Explain what a spectator ion is.
An ion that appears on both side of a complete ionic equation and does not directly participate in the reaction.
Lesson 88 pages 447-450... Question 8: Which combination of reactants would result in a neutralization reaction with sodium nitrate, NaNO3, as one of the products? A.) Mg(NO3)2 + NaOH B.) HNO3 + NaOH C.) CH3OH + NaOH D.) HNO3 + NaCl
B.) HNO3 + NaOH - (Because the other product would be H2O which is necessary)
Lesson 72 pages 371-374... Question 1: Why do chemical equations need to be balanced?
Because the reactants have to have the same mass as the products because of the law of conservation of mass.
Lesson 88 pages 447-450... Question 4: Predict the products for the reactions given below. Be sure to balance each equation. h.) CH3COOH(aq) + NH4OH(aq) →
CH3COONH4(aq) + H2O(l)
Lesson 88 pages 447-450... Question 4: Predict the products for the reactions given below. Be sure to balance each equation. d.) CH3COOH(aq) + NaOH(aq) →
CH3COONa(aq) + H2O(l)
Lesson 70 pages 363-366... Question 6 A: Classify the following two changes as physical or chemical. Explain your reasoning. CaCO3(s) + H2SO4(aq) → CaSO4(aq) + CO2(g) + H2O(l)
Chemical because the chemical formulas changed to create a new substance
Lesson 73 pages 375-378... Question 1: How are combination reactions and decomposition reactions related?
Combination reactions are reactions that has two molecules on the product side and they combine into one product and decomposition reactions are reactions that have one reactants and it breaks down into two products.
Lesson 88 pages 447-450... Question 7: Which of these substances may be useful in neutralizing a lake damaged by acid rain? A.) H2SO4 B.) CH3COOH C.) CaCl2 D.) Ca(OH)2
D.) Ca(OH)2 (Because it has a base, OH.)
Lesson 90 pages 457-460... Question 5: Name solutions you can combine that will precipitate each of the compounds listed. b.) FePO4
FeCl3(aq) + Na3PO4(aq)
Lesson 90 pages 457-460... a.) Hg(NO3)2 (aq) +2 NaCl (aq) → HgCl2 (s) + 2NaNO3(aq) Write the net ionic equation:
Hg2+(aq) + 2Cl-(aq) → HgCl2 (s)
Lesson 90 pages 457-460... a.) Hg(NO3)2 (aq) +2 NaCl (aq) → HgCl2 (s) + 2 NaNO3(aq) Write the complete ionic equation:
Hg2+(aq) + 2NO3-(aq) + 2Na+(aq) + 2Cl-(aq) → HgCl2 (s) + 2NO3-(aq) + 2Na+(aq)
Lesson 73 pages 375-378... Question 2: What is the difference between a single exchange reaction and a double exchange reaction?
In a single exchange reaction the atoms of an element are exchanged with atoms of another element in a compound. In a double exchange reaction two compounds exchange atoms with each other. The general equation for a single exchange reactions is A + BC → AC + B. The general equation for a double exchange reaction is AB + CD → AD + CB.
Lesson 69 pages 358-362... Question 5: It's extremely dangerous to mix bleach and ammonia because highly toxic gas will form. So you should never mix these two chemicals. The two chemical reactions below describe what would happen if bleach and ammonia were mixed. If these reactions were carried out by a professional chemist using proper safety precautions in a controlled environment, what might that chemist observe in each case? NaOCl (aq) +NH4OH (aq) ---> NH2Cl (g) + NaOH (aq) + H2O (l) NaOCl (aq) + 2NH4OH (aq) ---> N2H4 (g) + NaCl (aq) + 3H2O (l)
In both situations the mixture of two clear solutions produces gas bubbling out of the resulting solution.
Lesson 70 pages 363-366... Question 2: Explain why dissolved can either be described as a physical or chemical change?
Ionic compounds dissolved in water conduct electricity but ionic solids do not and since the properties changed it could be considered a chemical changes, but you can recover solid compounds from solutions by evaporating the water they are dissolved in.
Lesson 90 pages 457-460... Question 4: Highlight the ionic solids that are soluble in water. LiNO3 CaCO3 KCl Li2CO3 MgCl2 PbCl2 Ca(OH)2 AgCl RbOH
LiNO3 KCl Li2CO3 MgCl2 RbOH
Lesson 69 pages 358-362... Question 2: Use chemical equations to describe the difference between sugar melting and sugar decomposing. The formula for sugar is C12H22O11.
Melting: C12H22O11(s) → C12H22O11(l) Decomposing: C12H22O11(s) → 12C(s) + 11H2O(g)
Lesson 88 pages 447-450... Question 4: Predict the products for the reactions given below. Be sure to balance each equation. e.) 2HNO3(aq) + Mg(OH)2(aq) →
Mg(NO3)2(aq) + 2H2O(l)
Lesson 73 pages 375-378... Question 4: List four ionic compounds in the reactions from question 3.
MgBr2, NaOH, HNO3, C2H4
Lesson 88 pages 447-450... Question 4: Predict the products for the reactions given below. Be sure to balance each equation. b.) 2HCl(aq) + Mg(OH)2(aq) →
MgCl2(aq) + 2H2O(l)
Question 4 B: Write a chemical equation for these reaction descriptions. -Solid magnesium sulfide is heated to produce solid magnesium and sulfur gas
MgS(s) → Mg(s) + S(g)
Lesson 88 pages 447-450... Question 4: Predict the products for the reactions given below. Be sure to balance each equation. j.) H2SO4(aq) + Mg(OH)2(aq) →
MgSO4(aq) + 2H2O(l)
Lesson 88 pages 447-450... Question 4: Predict the products for the reactions given below. Be sure to balance each equation. c.) HF(aq) + NH4OH(aq) →
NH4F(aq) + H2O(l)
Lesson 88 pages 447-450... Question 4: Predict the products for the reactions given below. Be sure to balance each equation. f.) HNO3(aq) + NH4OH(aq) →
NH4NO3(aq) + H2O(l)
Lesson 90 pages 457-460... Question 5: Name solutions you can combine that will precipitate each of the compounds listed. d.) AgCl
NaCl(aq) + AgNO3(aq)
Lesson 90 pages 457-460... Question 5: Name solutions you can combine that will precipitate each of the compounds listed. c.) HgCl2
NaCl(aq) + Hg(NO3)2(aq)
Lesson 69 pages 358-362... Question 4 A: Write a chemical equation for these reaction descriptions. -Solid sodium chloride dissolves in water
NaCl(s) → NaCl(aq)
Lesson 88 pages 447-450... Question 4: Predict the products for the reactions given below. Be sure to balance each equation. a.) HF(Aq) + NaOH(aq) →
NaF(aq) + H2O(l)
Lesson 70 pages 363-366... Question 6 B: Classify the following two changes as physical or chemical. Explain your reasoning. NaCl(s) → NaCl(l)
Physical because it is still sodium chloride it just changed states, from a solid to a liquid.
Lesson 68 pages 353-357... Question 1: What is the difference between a reactant and a product?
Reactants are the substances you start with in a chemical equation and products are the substances that you end with.
Lesson 69 pages 358-362... Question 3 A: Describe what you think you would observe for these chemical equations. Mg(s) + 2HCl(aq) → H2(g) + MgCl2 (aq)
Solid magnesium will react and disappear into an aqueous compound, and gas bubbles will appear.
Lesson 90 pages 457-460... Question 1: Describe what a precipitate is and how it forms.
Sometimes certain anions and cations combine and come out of solution as a solid, or a precipitate. This kind of reaction is called a precipitation reaction. A precipitate is an insoluble compound that forms as a product of a chemical reaction as a solid.
Lesson 90 pages 457-460... Question 2: What does solubility have to do with precipitation from solution?
Substances with a lot solubility tend to form precipitates in aqueous solutions.
Lesson 71 pages 367-370... Question 1: Explain the law of conservation of mass.
The law of conservation of mass states that mass is conserved during chemical and physical changes because no atoms are created or destroyed.
Lesson 71 pages 367-370... Question 5: Explains what happens to the number of atoms, the mass, and the weight of the water in a glass when it evaporates.
The number of atoms stays the same, it is still made of H2O molecules. The mass and weight also stay the same because there is the same number of atoms.
Lesson 88 pages 447-450... Question 4: Predict the products for the reactions given below. Be sure to balance each equation. i.) H2SO4(aq) + HNO3(aq) →
There is no base present therefore there cannot be a reaction.
Question 4 C: Write a chemical equation for these reaction descriptions. c.) -titanium dioxide
Ti(s) + O2(g) → TiO2(s)
Lesson 69 pages 358-362... Question 1: In words, describe the difference between sugar melting and sugar dissolving in water. The formula for sugar is C12H22O11.
When sugar dissolves the sugar molecules spread throughout the water and it changes from the solid phase to the aqueous phase, and when sugar melts it changes from the solid phase to the liquid phase.
Lesson 90 pages 457-460... Question 7: Which of the following equations that represents a precipitation reaction? a.) 2NaCl(aq) + Hg(NO3)2(aq) → HgCl2(aq) + 2NaNO3(aq) b.) 2 NaOH(aq) + CaCl2(aq) → Ca(OH)2(s) +2NaCl(aq) c.) K2CO3(aq) + 2LiNO3(aq) → Li2CO3(aq) + 2KNO3(aq) d.) 3Zn(NO3)2(aq) + 2Na3PO4(aq) → Zn3(PO4)2(s) + 6NaNO3(aq) e.) Ca(NO3)2 (aq) +2NaCl (aq) → CaCl2(aq) + 2NaNO3(aq)
a, b, and d
Lesson 90 pages 457-460... Question 6: Write balanced chemical equations for these reactions. Make sure to indicate which substances are aqueous and which are solid. a.) 2NaCl(aq) + Hg(NO3)2(aq) →
a.) 2NaCl(aq) + Hg(NO3)2(aq) → HgCl2(aq) + 2NaNO3(aq)
Lesson 90 pages 457-460... Question 5: Name solutions you can combine that will precipitate each of the compounds listed. a.) CaCO3
a.) Ca(NO3)2(aq) + Na2CO3(aq)
Lesson 73 pages 375-378... Question 3: Name wether the following reactions are double exchange, single exchange, or combination. a.) NaOH(aq) + HNO3(aq) → NaNO3(aq) + H2O (l) b.) C2H4(g) + Cl2(g) → C2H4Cl2(g) c.) Cl2(g) + MgBr2(s) → Br2(s) + MgCl2 (s)
a.) Double exchange reaction b.) Combination reaction c.) Single exchange reaction
Lesson 71 pages 367-370... Question 3: Below is a chemical equation along with a verbal description of the reaction. Verbal Description: Gaseous sulfur trioxide is added to liquid water to produce aqueous sulfuric acid. Chemical Equation: SO3(g) + H2O(l) → H2SO4(aq) a.) Was matter lost or gained during the reaction? b.) The left side of the equation shows one atom of S, two atoms of H, and four atoms of O. How many atoms of each element are on the right side of the equation? How does this provide evidence for the law of conservation of mass?
a.) Explain how you could prove this by taking measurements. No because the law of conservation of mass states that no matter can be lost or gained during a reaction. You could prove this by comparing the weight of the reactants to the weight of the product. b.) There is the same number of the same atoms on the reactant side of the equation, this proves that the mass will stay the same throughout a reaction.
Lesson 73 pages 375-378... Question 5: Sulfur trioxide gas combines with liquid water to produce aqueous sulfuric acid: _______(g) + H2O(l) → H2SO4(aq) a.) predict the missing reactant b.) balance the equation c.) explain how these toxic substances could enter the body.
a.) SO3 b.) Already balanced c.) Since SO3 is a gas it could enter the body through the nose or mouth and travel through the lungs. Sulfuric acid is an aqueous liquid that could enter the body through ingestion or through the skin.
Lesson 72 pages 371-374... Question 3: Your recipe for banana bread call for two ripe bananas. However, you have six ripe bananas that you want to use before they go bad. a.) How can you make banana bread with all six bananas? b.) How is this related to balancing a chemical equation?
a.) You would triple the recipe b.) It is related because if the ratio is off between the banana to the other ingredients in the banana bread, then the chemical reaction will be different and the banana bread will not bake correctly, just like a chemical reaction needs to be balanced.
Lesson 73 pages 375-378... Question 7:Aqueous silver nitrate and aqueous sodium hydroxide are mixed to produce aqueous sodium nitrate and solid silver hydroxide: AgNO3(aq) + NaOH(aq) → NaNO3(aq) + ____ a.) predict the missing reactant b.) balance the equation c.) explain how the reactions could help remove toxic substances from the body.
a.) the missing product is AgOH(s) b.) the equation is already balanced c.) The Ag+ ion is insoluble in the molecule, AgOH(s). It is a solid that could then be filtered out. Ag+ (along with the OH- anion) can easily be removed from the water. The same type of reaction could be used to get rid of particularly toxic transition metal cations (like Pb2+) since all transition metal hydroxides are insoluble.
Lesson 73 pages 375-378... Question 6: Solid lithium reacts with aqueous hydrochloric acid to produce hydrogen gas and aqueous lithium chloride: Li(s) + HCl(aq) → H2(g) + ______ a.) predict the missing reactant b.) balance the equation c.) explain how these toxic substances could enter the body.
a.) the missing product is LiCl(aq) b.) the balanced equation would be: 2Li(s) + 2HCl(aq) → H2(g) + 2LiCl(aq) c.) Since lithium is a solid, these toxins could enter the body through ingestion or contact with skin.
Lesson 90 pages 457-460... Question 6: Write balanced chemical equations for these reactions. Make sure to indicate which substances are aqueous and which are solid. b.) 2 NaOH(aq) + CaCl2(aq) →
b.) 2 NaOH(aq) + CaCl2(aq) → Ca(OH)2(s) +2NaCl(aq)
Lesson 71 pages 367-370... Question 4: When an ice cube melts, which of these quantities will change? a.) The # of atoms it contains b.) It's mass c.) Its volume d.) All of the above e.) None of the above
c.) Its volume
Lesson 90 pages 457-460... Question 6: Write balanced chemical equations for these reactions. Make sure to indicate which substances are aqueous and which are solid. c.) K2CO3(aq) + 2LiNO3(aq) →
c.) K2CO3(aq) + 2LiNO3(aq) → Li2CO3(aq) + 2KNO3(aq)
Lesson 90 pages 457-460... Question 6: Write balanced chemical equations for these reactions. Make sure to indicate which substances are aqueous and which are solid. d.) 3Zn(NO3)2(aq) + 2Na3PO4(aq) →
d.) 3Zn(NO3)2(aq) + 2Na3PO4(aq) → Zn3(PO4)2(s) + 6NaNO3(aq)
Lesson 90 pages 457-460... Question 6: Write balanced chemical equations for these reactions. Make sure to indicate which substances are aqueous and which are solid. e.) Ca(NO3)2 (aq) +2NaCl (aq) →
e.) Ca(NO3)2 (aq) +2NaCl (aq) → CaCl2(aq) + 2NaNO3(aq)
