Name: ______Class: ______Date: ______

Exam #1 Review

  1. Know your Lab Safety Rules. List 5 rules that you DON’T know as well as the others.

(See Lab Safety Rules link)

  1. What are the 3 types of science investigations? Describe each one.

Comparative - Involve collecting data on different populations/organisms, under different conditions (ex. Times of year, locations), to make a comparison.

Example – Using a hand lens to examine the color and texture of four different rocks.

Experimental - Involve a designed test in which variables are changed, controlled, and measured in an effort to gather evidence to support or disprove a hypothesis.

Example – Planting rye grass seeds in potting soil in three plastic cups, placing them on a window sill, and watering one daily, one every third day, and one not at all.

Descriptive - Involve describing and/or quantifying parts of a natural system.

Example – Measuring the width of a desk with a meter stick.

  1. What is an independent variable? What is a dependent variable?

Independent/Manipulated Variable: factor or condition in an experiment that is changed on purpose by you, the scientist. This goes on the X axis of a graph. (Bottom)

Dependent/Response Variable: factor or condition in an experiment that changes as a result of the independent variable. This is what you measure and goes on the Y axis. (Side)

  1. What is a control group? What are constants?

Control: a set up without the variable being tested.

Constant: factors or conditions that are kept the same in all trials of the experiment.

  1. What is the difference between accuracy and precision?

Accuracy: how close a measured value is to the actual (true) value.

Precision: how close the measured values are to each other.

  1. What is the difference between qualitative and quantitative data?

Quantitative Data: Observation that DOES involve a number/measurement (has magnitude size or amount) Ex. Length, mass, volume

Qualitative Data: Observation that DOES NOT involve a number/measurementEx. Presence of odor, color change

  1. What is the difference between an observation and an inference?

Inference: drawing conclusions (making assumptions) based on your observations.

Observation: using your five senses to describe something.

  1. What is the difference between intensive and extensive physical properties? List 3 examples of each.

Intensive Property: physical property that does not depend on the amount of matter present; observation/measurement does not change. Ex: Density, Color and Temperature

Extensive Property: physical property that does depend on the amount of matter present; observation/measurement does change. Ex: Mass, length, Volume

  1. Know your lab equipment functions and be able to identify them. List the name and function of 5 pieces of lab equipment that you DON’T know as well as the others.(See Lab Equipment Notes link)
  1. Define matter.Matter is anything that takes up space and has volume!
  2. What are the 5 signs that a chemical change has occurred?

  1. Heat released or absorbed
  2. Color change
  3. Gas Produced
  4. Precipitate forms
  5. Not easily reversible

  1. Determine if the change is physical or chemical:

  1. Salt dissolving in waterphysical
  2. Frying an eggchemical
  3. Iron rustingchemical
  4. Reshaping play-dohphysical
  5. Baking a cakechemical
  6. Milk souringchemical
  7. Water freezingphysical
  8. Cutting paperphysical
  9. Mixing ketchup and mustard physical
  10. Lighting a match chemical

  1. Define the following:

  1. Physical Property
  2. Chemical Property

•Boiling Point

•Color

• Smell

• Mass

• Volume

• Length

•HOW IT REACTS CHEMICALLY!!!

• Flammable?

• Combustible?

• Reacts with other substances?

  1. Define the following:

  1. Pure Substance
  2. Mixture

•Made up of the same 1 type of substance.

•Can’t be broken down.

•Two or more substances combined; neither identity is changed.

•Substances in a mixture do not interact with each other.

•DO NOT have specific compositions.

•Can easily be separated physically

  1. True/False: Compounds can be separated into individual elements by physical means.
  1. What is an alloy? List 3 examples.

A mixture of 2 or more metals or a metal and non-metal. Examples are Bronze, Steel and Brass

  1. Classify the following matter as either Pure Substance or Mixture, then as an Element, Compound, Homogeneous Mixture, or Heterogeneous Mixture:

  1. Gold (Au)Element
  2. AirMixture - HOM
  3. Glucose (C6H12O6)Compound
  4. Vegetable SoupMixture - HET
  5. Salt WaterMixture - HOM
  6. Orange Juice with PulpMixture - HET
  7. WaterCompound
  8. Kool-AidMixture - HOM
  9. Magnesium (Mg)Element
  10. ConcreteMixture - HOM
  11. Hydrogen Peroxide (H2O2)Compound
  12. BrassMixture - HOM

  1. Write the formula for each of the following matter examples and classify it as either Element, Compound, or Mixture (of what?).

Formula: 2B2W + 2BFormula: 4B + 3W

Description: Mixture of elements and compoundsDescription: Mixture of elements

  1. Convert the following numbers into scientific notation:

  1. 0.000043 4.3x10-5
  1. 201,0002.01x105
  2. 0.00242.4 x 10-3
  1. 71007.1 x 103

  1. Convert the following numbers into standard notation:

  1. 2.50 x1062,500,000
  1. 1.86 x 10-40.000186
  1. 5.2 x 105520,000
  1. 7.0 x 10-50.000070

  1. Count the number of significant figures in the following numbers:

  1. 0.000562 sig figs

All zeroes to the left are never significant

  1. 280.0 4 sig figs

All zeroes to the right are significant if there is a decimal in the number

  1. 5,300.1 5 sig figs

All zeroes are significant if they are in the middle of two numbers

  1. 75,0002 sig figsZeroes are never significant if they are to the right of a number and if there is no decimal anywhere in the number

Make sure you study your notes! (Lab Safety Rules, Lab Equipment Functions & Identification, Science Investigations, Scientific Notation and Significant Figures, Matter, AND study your definitions!!