Chemistry Physical and Chemical Changes Quiz

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Questions and Answers

What occurs during a physical change?

Bonds are broken and formed.

Substances are transformed into new substances.

Intermolecular forces may be severed or formed. (correct)

Temperature always increases.

Which of the following is a sign of a chemical change?

Melting of ice

Formation of a precipitate (correct)

Size change of a substance

Change in temperature due to heating

What type of change occurs when water evaporates?

Phase change - liquid to gas (correct)

Chemical change - color change

Physical change - temperature increase

Chemical change - gas formation

Which of the following indicates a change in chemical composition?

Formation of gas from solid reactants Signup and view all the answers

Which of the following is NOT a sign of a chemical reaction?

Phase change Signup and view all the answers

Which process involves the breaking and forming of chemical bonds?

Chemical change Signup and view all the answers

What is typically produced during a chemical reaction?

New substances Signup and view all the answers

Which observation would most likely indicate a chemical change?

Gas bubbles forming in a liquid Signup and view all the answers

How many moles of carbon dioxide can be produced from 64 grams of methanol?

1.5 moles Signup and view all the answers

What does the equivalence point in a titration indicate?

The analyte is totally consumed Signup and view all the answers

Which piece of laboratory equipment is used to add small volumes of liquid during a titration?

Buret Signup and view all the answers

What happens at the endpoint of a titration?

A permanent color change is observed Signup and view all the answers

What is the molar mass of methanol?

32 g/mol Signup and view all the answers

In a redox titration, which solution would most likely be the titrant?

A solution that changes color at the endpoint Signup and view all the answers

What should be done before filling the buret with titrant?

Rinse the buret with a portion of the titrant Signup and view all the answers

Which of the following describes an analyte in titration?

The solution whose concentration is being determined Signup and view all the answers

What happens to hydrogen bonds during the evaporation of ammonia?

They are broken as ammonia molecules enter the gas phase. Signup and view all the answers

How can the amounts of products be calculated in a reaction?

By using the balanced reaction equation. Signup and view all the answers

What is the correct relationship found in the coefficients of a balanced chemical equation?

They indicate the proportions of the amounts of substances involved. Signup and view all the answers

In the reaction of Cu3(PO4)2 with H2SO4, how many moles of Cu2+ are produced from 30 mL of 1.5 M sulfuric acid?

0.015 mol Signup and view all the answers

What is the percent yield if 11.0 g of calcium chloride produces 6.6 g of hydrochloric acid?

91% Signup and view all the answers

In the reaction 4NH3 + 5O2 → 4NO + 6H2O, which reactant is the limiting reagent if 3.25 g of NH3 is used?

It can only be determined through calculations. Signup and view all the answers

What type of interaction occurs when salt dissolves in water?

Ion-dipole interactions between ions and solvent. Signup and view all the answers

Which calculation is most directly related to stoichiometry?

Calculating amounts of reactants and products. Signup and view all the answers

What is the net ionic equation for the reaction involving Pb2+ and I-?

Pb2+(aq) + 2 I1-(aq) ---> PbI2 (s) Signup and view all the answers

Which ions are considered spectator ions in the given reaction?

Na1+ and NO31- Signup and view all the answers

What type of reaction is demonstrated by the formation of PbI2?

Precipitation reaction Signup and view all the answers

Which of the following correctly represents a chemical process?

Burning wood Signup and view all the answers

What is a characteristic of physical processes compared to chemical processes?

They typically involve changes in intermolecular interactions. Signup and view all the answers

How can you interpret the dissolution of salt in water?

It can be viewed as a physical or chemical process. Signup and view all the answers

What is the complete molecular equation for the reaction between K3PO4 and Al(NO3)3?

K3PO4 (aq) + Al(NO3)3 (aq) ---> AlPO4 (s) + 3 KNO3 (aq) Signup and view all the answers

In the reaction, what forms when F- reacts with H+?

HF(s) Signup and view all the answers

In the reaction Fe2+ + Ce4+ → Fe3+ + Ce3+, which species is being oxidized?

Fe2+ Signup and view all the answers

Which of the following ions is ALWAYS soluble in water?

Nitrate (NO3-) Signup and view all the answers

What is the oxidation number of oxygen in a peroxide ion (O2^2-)?

-1 Signup and view all the answers

In the precipitation reaction AgNO3(aq) + KCl(aq) → AgCl(s) + KNO3(aq), which product is the insoluble salt?

AgCl Signup and view all the answers

What is the rule for determining the oxidation number of hydrogen?

-1 when bonded to a metal and +1 when bonded to a nonmetal Signup and view all the answers

What is the sum of the oxidation numbers in a neutral compound?

0 Signup and view all the answers

Which ion has an oxidation number of -1 under most circumstances?

Fluorine (F) Signup and view all the answers

In a polyatomic ion, what does the sum of the oxidation numbers equal?

The charge on the ion Signup and view all the answers

What is the oxidation half-reaction for the reaction between Zn and CuSO4?

Zn → Zn2+ + 2e– Signup and view all the answers

What is the reduction half-reaction for the reaction with Cu2+?

Cu2+ + 2e– → Cu Signup and view all the answers

Which of the following describes a net ionic equation correctly?

It contains only species that change during the reaction. Signup and view all the answers

Which statement about oxidation numbers is correct?

Oxidation numbers are assigned to individual atoms in a molecule. Signup and view all the answers

What is the complete balanced reaction for the half reactions Cu2+ → Cu+ and Pb2+ → Pb4+?

2 Cu2+ + Pb2+ → 2Cu+ + Pb4+ Signup and view all the answers

When applying the equation M1V1 = M2V2 in titration, what is a potential pitfall?

This equation must always be used in REDOX titrations. Signup and view all the answers

Which of the following best describes a polyatomic ion in solution?

It remains as a compound with the same charge. Signup and view all the answers

In identifying the substances oxidized or reduced, which of the following is important?

Observing the change in oxidation numbers. Signup and view all the answers

What does the reaction Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu indicate?

Zinc undergoes oxidation and copper undergoes reduction. Signup and view all the answers

Study Notes

Unit 4 Review - Chemical Reactions

Chemical changes involve the transformation of substances into new substances with different compositions. Evidence includes heat or light production, gas formation, precipitate formation, and color change.
Physical changes alter a substance's properties without changing its composition. Examples include phase changes (solid, liquid, gas) and mixtures.
Physical changes do not involve breaking or forming chemical bonds, only intermolecular forces may be altered.
Chemical changes involve breaking and forming chemical bonds.
A student mixing silver nitrate and potassium chloride, resulting in a cloudy solution is an example of a chemical change (precipitate formation).
When liquid water evaporates, intermolecular forces between water molecules are being severed.
A colorless solution turning pink indicates a chemical change.
Production of heat when hydrogen peroxide mixes with potassium iodide points to a chemical change.
Ammonia evaporating from a beaker involves the breaking of hydrogen bonds, causing molecules to separate and enter the gaseous phase.
Balanced chemical equations represent chemical reactions, showing reactants and products and their stoichiometric ratios.
The total number of atoms of each element must be the same on both sides of the equation.
Balanced molecular equations, complete ionic equations, and net ionic equations are used to represent chemical reactions.
Net ionic equations only include species involved in the reaction and do not include spectator ions
To balance combustion reactions, balance carbon then hydrogen, then oxygen.
Molecular equations represent all reactants and products.
Complete ionic equations separate all ions that participate in the reaction.
Precipitation reactions result in an insoluble ionic compound.
Common soluble salts include sodium, potassium, ammonium, and nitrate salts
Types of reactions include acid-base (proton transfer), oxidation-reduction (electron transfer), and precipitation (formation of an insoluble solid).
Acid-base reactions involve the transfer of protons between chemical species.
Oxidation-reduction reactions (Redox) involve the transfer of electrons between species, indicated by changes in oxidation numbers.
The oxidation number of an element in its elemental form is zero.
Oxidation numbers can be assigned to atoms in compounds.
Oxidation is loss of electrons; reduction is gain of electrons (OIL RIG).
Determining the limiting reactant involves calculating the amount of product formed based on the amount of each reactant present.
In a chemical reaction, atom conservation is essential.
Stoichiometric calculations use balanced chemical equations and mole ratios to determine the amounts of reactants and products.
Theoretical yield is the maximum amount of product that can be produced based on stoichiometry.
Actual yield is the amount of product obtained from a laboratory experiment.
Percent yield is a measure of the efficiency of a chemical reaction, calculated by dividing the actual yield by the theoretical yield and multiplying by 100%.
Titration is a technique to determine the concentration of an unknown solution (analyte) by reacting it with a solution of known concentration (titrant).
The equivalence point is where the analyte is fully consumed and indicated by a change in a property that can be monitored using an indicator (e.g., color change).
The endpoint is the observable event (often a color change) that signals the equivalence point in a titration.
Titration involves precise measurements of solution volumes.

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Test your understanding of physical and chemical changes with this engaging quiz. Explore topics such as signs of chemical reactions, titration processes, and the principles of bonds. Perfect for students delving into chemistry concepts and laboratory practices.