chemistry review 2.2 & 2.3 physical properties and chemical properties

a substance that has little tendency to change into other substances is said to have low

viscosity

suppose you need to identify the material in an object without changing the object in any way.should you use physical properties or chemical properties to identify the material? explain your choice.

you should use physical properties because if you used chemical properties,you would have changed the material in the object.

Formation of a precipitate is usually evidence of

chemical change

what is it called when the composition of matter changes?

chemical change

examples of physical changes

melting and freezing

List examples of physical properties.

-color -smell -volume -mass -density

Based on these pieces of pottery found in Grand Canyon National Park, would you describe pottery as a malleable or brittle material?

brittle

physical change

A change in a substance that does not involve a change in the identity of the substance

chemical change

A change in matter that produces one or more new substances

physical property

A characteristic of a pure substance that can be observed without changing it into another substance

chemical property

A characteristic of a pure substance that describes its ability to change into different substances

Viscosity

A liquid's resistance to flowing

how do chemical changes differ from physical changes?

A physical change in a substance doesn't actually change what the substance is. It remains the same. In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.

Filtration

A process that separates materials based on the size of their particles.

Distillation

A process that separates the substances in a solution based on their boiling points

precipitate

A solid that forms from a solution during a chemical reaction.

which action involves a chemical change?

Baking a cake

Why would you expect the materials used to make potholders to be poor conductors of heat?

Because potholders are not metals so it's hard to conduct heat through.

If you spill household bleach on your denim jeans you will observe that the are of the spill no longer has a blue color is this chemical or physical give a reason for your answer

Chemical the jeans will never be able to turn back to normal after being bleached

A pat of butter melts and then burns in a hot frying pan which of these changes is physical and which is chemical.

Melting is physical and the burning is a chemical change

Describe three uses of physical properties

Physical properties are used to identify a material, to choose a material for a specific purpose, or to separate the substances in a mixture.

Conductivity

The ability of an object to transfer heat or electricity to another object.

Reactiviy

The ease and speed with which an element combines, or reacts, with other elements and compounds.

boiling point

The temperature at which a liquid changes to a gas

melting point

The temperature at which a solid becomes a liquid

Gold platinum are often used to make jewelry what can you infer about the reactivity if these elements

They are not very reactive so they are less vulnerable to tarnish and rust

during which these events does a chemical change occur?

a cake rises in the oven

suppose you mix two colorless liquids together and a green sold settles to the bottom of the container. explain why you might be confident that chemical change has taken place.

because a compound and its elements are different substances, a chemical change has taken place.the compound has become new different substances.

explain why sharpening a pencil is an example of a physical change?

because when you sharpen a pencil it is still a pencil you are just changing how its appearance looks.

which property can be used to separate a mixture by distillation?

boiling point

List three common types of evidence for a chemical change.

change in color production of gas formation of a precipitate

what will heating a liquid do to it viscosity

decrease viscosity

true or false: each pure substance has its own unique density that can be used to help identify the substance.

false

two common separation methods

filtration and distillation

which of the following density,hardness,flammability,and melting point is not an example of a physical property.

flammability

what will putting a liquid in a refrigerator do to its viscosity?

increase viscosity

when you describe a liquid as a thick, are you saying that it has a high or low viscosity?

low viscosity example: maple syrup high viscosity: water

a material that can be hit without it shattering is called?

malleable

Density

mass/volume

a solid rectangular object floats on water is it possible that the block is pure gold?

no , because the gold is more dense than the water.

under what conditions can chemical properties be observed?

only when the substances in a sample of matter are changing into different substances.

explain why painting an iron railing can slow down the rate at which it rusts.

painting an iron railing will slow down the rate at which it will rust because something that is covering the iron from the ari/oxygen.

Is density a physical or chemical property?

physical

A sample of copper can be drawn into a thin wire. Is this property of copper a physical property or a chemical property? Explain.

physical because the composition of copper does not change as its shape changes.

name one physical property and one chemical property

pp=texture cp=burn

examples of chemical changes

rusting, burning

what allow a mixture to be separated by filtration?

size of the particles

Malleablity

the ability of a solid to be hammered without shattering

flammablity

the ability of a substance to burn

You can be certain that a change is a chemical change if

the substance cannot be reversed