FLVS Chemistry: Module 1 Exam Review

Multiple Choice Format Questions:

• What knowledge is considered science (explain five different items)? (1.01)
  Science is the process of gaining new knowledge and is a body of knowledge. It is observable, replicable, reliable, testable and flexible.
  

• What types of questions cannot be answered by science? (1.01)
  Science cannot be applied to opinion and beliefs such as religion, art and philosophy. Questions that violate the five factors cannot be answered; observable, replicable, reliable, testable and flexible.
  

• List and briefly explain each step of the scientific method. (1.01)
  The six steps are: purpose/question, research, hypothesis, experimental testing, analysis/conclusion.

  • The purpose/question is what you are trying to find out based upon your observations of the world.

  • You always want to research what other scientists have observed and discovered already.

  • The hypothesis is your prediction of what will happen in your experiment.  The hypothesis relates your independent and dependent variables.

  • Once the hypothesis has been developed, the experiment will need to be designed and carried out.  In an experiment, you must identify the independent, dependent variables and all the controlled variables.

  • Once the experiment has been conducted, you will need to analyze and compare the data collected.

  • After you have analyzed your results, you will need to revisit your hypothesis and conclude whether or not it was correct.

• What makes science replicable? (1.01)
  Empirical evidence gained from an experiment can be replicated by other scientists.  The experiment must be the same (conditions, variables)
  

• List the instrument used to measure the volume of a liquid, mass, length, and density. List their corresponding SI / metric units. (1.02, 1.07)

  • Liquid volume: graduated cylinder; units include: L, mL

  • Mass: balance; units include: kg, g

  • Length: ruler; units include: cm, m

  • Density is a ratio so it must be calculated: d = m/V; Units: kg/m^3

• How do scientists record and report measurements taken on non-digital instruments to reflect uncertainty? (1.02, page 6)
  Scientists will estimate one decimal place past the smallest increment (graduation)
  

• Describe at least two types of physical properties of a gas and give an example. (1.04)
  A gas is highly compressible, has an indefinite shape and indefinite volume. An example of a gas is carbon dioxide.
  

• What is density a ratio of? (1.04)
  The density of an object is a ratio of the mass per unit volume.  Common units are: g/cm^3, g/mL. SI unit: kg/m^3
  

• Consider the following chemical or physical properties: corrosion, boiling point, rusting. Which one is different from the others, based on these two categories? (1.04)
  Corrosion and rusting are chemical properties as they change the chemical composition of the objects. Boiling point is different from the other two as it is a physical property. It can be observed without changing the chemical composition.
  

• Describe the average speed and particle attractions for all four states of matter. (1.04, page 2)
  The speed of molecules will increase as we go from solid to liquid to gas to plasma. The particle attraction will decrease as we go solid to liquid to gas to plasma.
  

• Compare and contrast physical and chemical properties. Give a few examples of each. (1.04)

  • Chemical properties change the substance’s molecular composition. Examples include rusting, flammability, corrosion and decomposition.

  • Physical properties can be observed without changing the chemical composition/identity. A few examples include state of matter change, ductility (stretch), density, malleability (hammer into thin sheet), solubility and compressibility.

• Compare and contrast intensive and extensive properties. Give a few examples of each. (1.04)

  • Intensive properties do not depend on the sample size. Magnetism, density and changes of matter (boiling, etc) are examples of intensive properties.

  • Extensive properties depend on the sample size. Shape, volume, length and mass are examples of extensive properties.

• Compare and contrast physical and chemical change. What clues do we have that each has happened? (1.04)

  • In a physical change, the size or shape could be altered

  • In a chemical change, we will form new substances, we may see smoke, bubbling, flames, color change, etc.

• What happens when the kinetic energy of a gas decreases? (1.05)
  Kinetic energy is what is needed to overcome the forces of attraction (intermolecular forces) to change the state of matter. If the kinetic energy is decreasing, the particles will slow down, temperature will decrease. If the kinetic energy decreases enough, the molecules will give in to the forces of attraction that bind them (change state of matter).
  

• Explain how the process of boiling water is a physical change? (1.05)
  A physical change is when a substance changes form without changing its molecular composition/structure. When we boil water, we are merely separating the water molecules from each other. We are not changing the composition or turning water into a different substance. We are only changing the state of matter, not the composition of matter.
  

• Explain how the process of baking a cake is a chemical change? (1.05)
  A chemical change is when the molecular composition/structure changes. When we add heat to the cake mixture, multiple chemical reactions occur.
  

• Compare and contrast the properties of pure substances and mixtures (1.06)

  • A pure substance consists of a single element or type of compound. For example, lead is a pure substance made from a single element and glue is made up of just one compound.

  • A mixture is created when solids, liquids, or gases mix with one another. Mixtures can occur with substances that are in the same states of matter or of different states of matter. Each substance in a mixture maintains its individual composition and property.

• Is salad dressing a pure substance or a mixture? (1.06)
  Salad dressing is a heterogeneous mixture as each spoon will have a different composition/seasoning. Each substance can be separated from the mixture by physical means.
  

• Describe why water is a compound and steel is a homogeneous mixture. (1.06)
  Water is made up of two elements that are chemically bonded to form the molecule H2O.  It is a chemical compound.

  
  Steel is a mixture as it is several elements/compounds that are mixed together, not bonded together.  The elements/compounds within steel keep their individual properties and composition.
  

• List and describe two ways we can physically separate a heterogeneous mixture. (1.06)

  • Filtration is a way to separate an insoluble solid from a liquid. Think of separating pepper out of water using a coffee filter.

  • Another technique is distillation. This is where we separate a liquid from a solution using heat. This is similar to distillation except that this technique captures the evaporated liquid and condenses it.

• What type of equipment would you use to hold a small amount of a substance? (Be able to describe all the lab equipment and their purpose) (1.07, page 5)
  A test tube is small and can hold a small amount of a substance. We would not want to use a large container, such as a beaker as it would significantly increase the uncertainty of the measurement.
  

• A student designed an experiment to see if the type of soil makes a difference in growing well. What is the independent variable? (1.07)
  The independent variable is the factor that the scientist changes, on purpose to see how it affects something else. In this experiment, the student scientist wants to see how different types of soil affect the growth. The independent variable is the type of soil.

Essay Format Questions:

• Compare the type of change that occurs when a substance condenses and when a substance corrodes. Use complete sentences to justify the type of change that occurs. (1.05)

  • Condensation: physical change as the composition of the substance is the same and the motion of the particles of the substance is altered as the heat is released.

  • Corrosion: chemical change as the composition of the substance is altered (bonds are broken, new substances are formed). The new compounds have different properties.

• A science student notices that a plant left in the sun for 30 minutes a day grew better than a plant with no sunlight. Suggest a suitable hypothesis that can be studied. What are the dependent, independent and controlled variables? (1.07)

  • The student noticed that sunlight affected the plant growth.

  • A suitable hypothesis: Exposure to sunlight for 30 minutes a day improves plant growth compared to plants without any sunlight exposure.

  • Independent variable: An independent variable is a variable that is manipulated or changed by the researcher in an experiment. It is the variable that is believed to cause a change in the dependent variable.

  • Dependent variable: A dependent variable is the variable that is being measured or observed in an experiment. It is the variable that is believed to be influenced or affected by the independent variable.

  • Controlled variable: A controlled variable is a variable that is kept constant throughout an experiment. It is used to ensure that any changes observed in the dependent variable are due to changes in the independent variable and not to other factors.

Honors Extension (MC & Essay format):

• (1.03H) List three pseudosciences and explain why they are not considered scientific.

  • Astrology is the belief that the position of the stars can give us information about a person. This cannot be proven reliable through testing with the scientific method.

  • Phrenology is where we read ‘bumps’ in a person’s skull to determine personality traits. This cannot be proven reliable through the scientific method.

  • Superstition is another pseudoscience. It is the belief that people have that certain things will bring them good or bad luck. Superstitions cannot be proven reliable through scientific method.

• (1.03H) Describe the four characteristics of a reliable investigation.
  A reliable investigation makes sense (follows logic), is reviewed by peers across the globe to reduce bias and is constantly reviewed, using the scientific method, to collect new evidence over a significant period.
  

• (1.03H) Compare and contrast a hypothesis and a theory.

  • Both types of scientific knowledge, hypothesis and theories, are developed using background research and can change over time using the scientific method.

  • The difference is that scientific theories are well-tested hypotheses. They are based on evidence gained through reliable investigations. Hypotheses, on the other hand, are predictions or tentative explanations of phenomena that have not yet been fully tested or have been disproven.