Name Date P. Lesson 3. Chemistry

Transcription

1 Name Date P Lesson 3 Chemistry

2 Student Lesson 3: Measurement and Chemistry Reference Sheet: Common chemistry and measurement terms: Mass, Matter, Volume, Density, Solid, Liquid, Gas, Element, Molecule, Atom, Particles, Periodic Table, Mixtures, Melting, Freezing, Evaporation, Condensation, Sublimation, Precipitate, Reaction, heat, H2O (HOH or water), Carbon Dioxide (CO2), ph, basic, acidic, temperature, chemicals, Bunsen burner, other lab tools, grams, meters, milliliters, kilograms, liter, cm³, etc. Mass: is the measure of how much matter is an object o Give the example of mixing baking soda and vinegar in a flask with a balloon over the top of the flask to create a closed system (where the chemical reaction is contained in one area). The mass of the flask was 25.6g after the reaction the mass of the flask was 23.2 g. THINK ABOUT IT Was matter destroyed in this experiment? Explain Answer: No it just changed states from a liquid to a gas. Matter cannot be created or destroyed Conservation of Matter Volume: amount of space an object takes up Units for : a) mass = grams b) volume = cm³ or ml Density = mass/ volume Phase Changes: Solid, Liquid and Gas o Melting: S-L o Freezing: L-S o Evaporate: L-G o Condensation: G-L OAA Science Lesson 3 27

3 Physical and Chemical Changes Physical Changes- reversible Phase Changes: Solid, Liquid, Gas Water Freezing/ Melting Breaking a Window Cutting an apple Peeling an orange Chemical- Non reversible Mixing Baking Soda and Vinegar Together Rusty Bike Digesting food House on fire Student Practice: Measurement and Chemistry 1) What unit of measurement is used for density? a. g b. cm³ c. g/cm d. g/ cm³ 2) The instructions for an experiment direct the students to put a liquid into a beaker and use a hot plate to heat the liquid to 100 C. Describe two safety precautions the students need to take while heating the liquid. Describe the movement of particles of the liquid once it reaches 100 C and the phase change. (4 Points) OAA Science Lesson 3 28

4 3) A glass of ice water sits outside in the sunlight, completely full. After about an hour there is no ice left. After three hours the glass of water is only half full. Describe what happened to the other half of the water, using the idea of conservation of matter and phase changes. (2 points). OAA Science Lesson 3 29

5 Use the information below to answer questions 4 6. Baking Soda and Vinegar Reaction Students perform a chemistry experiment by mixing baking soda with vinegar. They mix 4 grams of baking soda with 50 grams of vinegar in a 6-gram plastic cup as shown below. The cup is left uncovered. The students record the mass and temperature of the mixture every 5 seconds. They continue these observations until 10 seconds after they see the mixture stop bubbling. Their data are shown in the table below. OAA Science Lesson 3 30

6 4) Which graphs show the trends in the mass (M) and temperature (T) changes during the baking soda and vinegar reaction shown in the diagram? OAA Science Lesson 3 31

7 5) The data in the table show the temperature of the cup-baking soda-vinegar system. The temperature of the surrounding air was not measured. Assuming that the total amount of energy remains constant, what conclusion about energy transfer does the temperature data support? A. Thermal energy was lost from the surrounding air and the system. B. Thermal energy was gained by the system and the surrounding air. C. Thermal energy was transferred from the surrounding air to the system. D. Thermal energy was transferred from the system to the surrounding air. 6) The data show that the mass of the cup and its contents decreases while the mixture is bubbling. In your Answer Document, explain why the mass of the cup and its contents at 25 seconds is less than the initial total mass of the cup, baking soda and vinegar. Include in your answer a valid scientific reason on which you based your explanation. (2 points) OAA Science Lesson 3 32

8 7) A tightly sealed glass box has a mass of 20,000 grams and contains a 5-gram cube of ice, making the total mass 20,005 grams. The box with the ice is placed in direct sunlight. After three hours, the box appears to be empty, with just small droplets along the sides of the box. Which statement describes the mass of the sealed box after sitting in the sun? A. The mass decreases because the ice melted into a liquid. B. The mass remains the same as the ice melts and then evaporates. C. The mass increases as the gases inside the box absorb energy and expand. D. The mass increases as the water vapor condenses into small droplets on the glass. 8) A student studying rock densities needs to measure the volume of a small rock sample to the nearest milliliter (ml). The student knows that the rock sample has a volume of at least 5 ml. Which tool should the student use to get the most accurate measure of the volume of water displaced by the rock? OAA Science Lesson 3 33

9 Use the diagram and information below to answer question 9. 9) A teacher places a ribbon of magnesium on a wire and suspends it in a flask. She then seals the flask and runs electricity through the wire to ignite the magnesium.after the magnesium is completely burned, a student notices a white powder in the bottom of the flask. The mass of the flask system (the flask and its contents) is determined before and after the magnesium is ignited. Which statement correctly compares the mass of the flask system before the magnesium burned with the mass of the flask system after the magnesium burned? A. The mass of the flask system before burning is greater than the mass of the flask system after burning. B. The mass of the flask system before burning is less than the mass of the flask system after burning. C. The mass of the flask system before burning is the same as the mass of the flask system after burning. D. The mass of the flask system before burning is not related to the mass of the flask system after burning. OAA Science Lesson 3 34

10 Use the following information to answer question ) The table below lists the densities of several materials. Which material will float in water? A. limestone B. magnesium C. sulfur D. wax OAA Science Lesson 3 35

11 Use the information below to answer questions Density Experiment The two graduated cylinders pictured can hold the same amount of water and use the same scale. A student measures the masses of two metal balls. One ball is made of aluminum and the other ball is made of lead. The student adds 50 ml of water to each graduated cylinder and then drops one metal ball into each graduated cylinder. 11) Which tool did the student use to measure the mass of each metal ball? A. ruler B. timer C. balance D. graduated cylinder 12) The student includes the sentence below in the write-up of this investigation. The lead ball has a measured mass of 113 grams. Which kind of scientific statement is this sentence? A. inference B. prediction C. explanation D. observation OAA Science Lesson 3 36

12 13) The teacher asks the student to use the information she collected to compare the density of the two metal balls. The mass of the lead ball is 113 grams and the mass of the aluminum ball is 27 grams. What can the student infer about the density of these metal balls based on this investigation? A. The density of both metal balls is the same. B. The density of both metal balls is less than the density of the water. C. The density of the lead ball is less than the density of the aluminum ball. D. The density of the lead ball is greater than the density of the aluminum ball. 14) In repeating the investigation, the student accidentally drops and steps on the lead ball. This action changes its shape from a sphere to an egg-shaped solid. The lead ball is placed back into the graduated cylinder. In your Answer Document, predict what effect, if any, this change has on the amount of water displaced by the lead ball. Explain your prediction. (2 points) OAA Science Lesson 3 37

13 Use the information in the table below to answer questions Properties of Some Substances A scientist measures out 15 ml each of baking soda, salt, sugar, iron filings, and corn starch. She runs a series of procedures and records her results in the table below. The first column in the table indicates the procedure. The remaining columns indicate her results for each substance. 15. According to the information in the table, what comparison can the scientist make about the densities of sugar and corn starch? A. Sugar is more dense than corn starch. B. Corn starch is more dense than sugar. C. Sugar and corn starch have the same density. D. Both sugar and cornstarch are more dense than salt. OAA Science Lesson 3 38

14 16. The scientist observes the rust on the sample of iron filings and dries the sample thoroughly. The scientist weighs the entire sample and finds that it has more mass than the original 118 grams. What explains this increase in mass? A. The sample gained mass during drying. B. The sample gained mass during a physical change. C. The sample gained mass during a change of state. D. The sample gained mass during a chemical change. 17. What two changes does sugar undergo when heated in a spoon over a flame? A. two physical changes B. two chemical changes C. a chemical change and then a physical change D. a physical change and then a chemical change OAA Science Lesson 3 39

15 18. Which action demonstrates a chemical change? A. Long hair is cut and dried. B. A wooden pencil is sharpened and breaks. C. An ice cube melts and becomes a clear liquid. D. An iron nail becomes orange and flaky on the surface. 19. What evidence suggests that water goes through a physical change when it evaporates in the water cycle? A. The density of the water remains the same. B. The volume of the water remains the same. C. The physical properties of the water remain the same. D. The chemical properties of the water remain the same 20. Which describes a chemical change and a physical change that take place during the production of electricity in the coal-fired power plant (Figure 1)? A. The coal moving along the conveyor belt is a chemical change. B. The coal burning to give off heat and carbon dioxide gas is a chemical change. C. The boiling water turning to steam is a chemical change. D. The steam turning the turbine is a chemical change. 21. In any physical or chemical process, what two quantities are always conserved? A. matter and total energy B. light and acoustic energy C. density and thermal energy D. gravity and potential energy OAA Science Lesson 3 40