Which of the following are physical changes? List all that apply. (You can briefly explain your answers if you think any of them are not clear-cut) Hydrogen peroxide bubbles on a cut Sensitive documents are shredded Milk sours over time Water boils on the stove for pasta Silver tarnishes Bronze is melted down to cast a statue

Classify each of the following as (1) a physical property, (2) a physical change, (3) a chemical property, or (4) a chemical change. a. the process of burning a piece of newspaper b. the fact that metallic copper reacts with chlorine gas c. the process of melting ice d. the fact that metallic gold is a solid at room temperature

In each case, identify the italicized property as a physical or chemical property. Give a reason for your choice. The normal color of the element bromine is red-orange. Iron is transformed into rust in the presence of air and water. Dynamite can explode. Aluminum metal, the shiny “foil” you use in the kitchen, melts at 660 °C.

In each case, describe the change as a chemical or physical change. Give a reason for your choice. (a) A cup of household bleach changes the color of your favorite T-shirt from purple to pink. (b) The fuels in the space shuttle (hydrogen and oxygen) combine to give water and provide the energy to lift the shuttle into space. (c) An ice cube in your glass of lemonade melts.

All of the following processes involve a separation of either a mixture into substances or a compound into elements. For each, decide whether a physical process or a chemical reaction is required. a Sodium metal is obtained from the substance sodium chloride. b Iron filings are separated from sand by using a magnet. c Sugar crystals are separated from a sugar syrup by evaporation of water. d Fine crystals of silver chloride are separated from a suspension of the crystals in water. e Copper is produced when zinc metal is placed in a solution of copper(II) sulfate, a compound.

Identify the following properties as either extensive or intensive. volume temperature humidity heat boiling point

In the accompanying photo, you see a crystal of the mineral calcite surrounded by piles of calcium and carbon, two of the elements that combine to make the mineral. (The other element combined in calcite is oxygen.) Based on the photo, describe some of the physical properties of the elements and the mineral. Are any properties the same? Are any properties different? Calcite (the transparent, cube-like crystal) and two of its constituent elements, calcium (chips) and carbon (black grains). The calcium chips are covered with a thin film of calcium oxide.

Suppose someone emptied ball bearings into a container of salt. Could you separate the ball bearings from the salt? How? Would your method involve no change, be a physical change, or be a chemical change?

The following are properties of substances. Decide whether each is a physical property or a chemical property. a Chlorine gas liquefies at 35C under normal pressure. b Hydrogen burns in chlorine gas. c Bromine melts at 7.2C. d Lithium is a soft, silvery-colored metal. e Iron rusts in an atmosphere of moist air.

Classify each of the following as aphysical or chemicalchange or property. A fireplace poker glows red when you heat it in the fire. A marshmallow turns black when toasted Loo long in a campfire. Hydrogen peroxide dental strips will make your teeth whiter. If you wash your jeans with chlorine bleach, they will fade. If you spill some nail polish remover on your skin, it will evaporate quickly. When making ice cream at home, salt is added Lo lower the temperature of the ice being used to freeze the mixture. A hair clog in your bathroom sink drain can be cleared with drain cleaner. The perfume your boyfriend gave you for your birthday smells like flowers. Mothballs pass directly into the gaseous state in your closet without first melting. A log of wood is chopped up with an axe into smaller pieces of wood. A log of wood is burned in a fireplace.