Which physical form of matter has a definite volume, but no definite shape?
Select the correct answer below:
gas
solid
liquid
solid and gas | Correct answer:
liquid
Liquid is a physical form of matter that has a definite volume, but no definite shape. A solid has a definite volume and definite shape, and a gas has no definite volume or shape. |
Which of the following is NOT a physical change?
Select the correct answer below:
copper wire is coiled into a spring
food coloring is added to water
you blow dry your hair
fireworks are set off | Correct answer:
fireworks are set off
Fireworks utilize chemical reactions to create light and energy, so this is an example of a chemical change. |
Which of the following can only consist of only one kind of atom?
Select the correct answer below:
an element
a pure substance
a compound
a mixture | Correct answer:
an element
Elements consist of only one kind of atom. Compounds and mixtures consist of more than one type of atom. A pure substance is either an element or a compound, so it could consist of one type of atom, but it does not have to. |
An example of homogeneous mixture is:
Select the correct answer below:
muddy water
pure water
ice water
saline water | Correct answer:
saline water
A homogeneous mixture has uniform composition for any given sample. A saline water solution has equal parts of salt dissolved throughout. Muddy water and ice water are heterogenous mixtures while pure water is a compound (and a pure substance). |
Which of the following describes a chemical property of a substance?
Select the correct answer below:
the substance emits a gas when dropped in water
the substance is dark green
the substance is sour to the taste
the substance has a pleasant odor | Correct answer:
the substance emits a gas when dropped in water
If a gas is emitted, this indicates a chemical reaction has occurred, so assessing this reactivity is an example of a chemical property. |
Matter that will take the shape of its container, but not expand to fill it is in what phase?
Select the correct answer below:
solid
liquid
gas
none of the above | Correct answer:
liquid
Liquids have a definite volume, but no definite shape. This means that they will expand to fit the shape of their container, but not expand to fill it completely. |
All of the following are physical properties EXCEPT:
Select the correct answer below:
texture
density
toxicity
boiling point | Correct answer:
toxicity
All of the above are physical properties EXCEPT toxicity. Physical properties are characteristics of matter that can be seen about a substance without changing that substance's chemical composition. |
Which of the following CANNOT be classified as a compound?
Select the correct answer below:
carbon dioxide
sodium chloride
lithium
sugar | Correct answer:
lithium
Lithium is an element. The rest are made of multiple elements. |
A substance that has fixed volume, but no fixed shape is a:
Select the correct answer below:
solid
liquid
gas
None of the above | Correct answer:
liquid
A liquid, like water, has a specific volume that can be measured, but it will take on the shape of whatever vessel it is stored in--whether it is a pot, a cup, a bathtub, or a swimming pool. |
Which is an example of a homogeneous mixture?
Select the correct answer below:
air
breakfast cereal
soil
oxygen | Correct answer:
air
Air is an example of a homogeneous mixture, oxygen is an element and the remaining options are heterogenous mixtures. |
When a physical change is observed:
Select the correct answer below:
it means a chemical property has changed
it means a physical property has changed
the substance cannot have also undergone a chemical change
the substance must have also undergone a chemical change | Correct answer:
it means a physical property has changed
An observed physical change corresponds to a change in a physical property like phase, hardness, or density. Physical changes can be caused by chemical changes, but are not necessarily indicative of a chemical change. |
A(n) ________ change occurs as a result of a chemical reaction.
Select the correct answer below:
electrical
chemical
physical
kinetic | Correct answer:
chemical
A chemical change occurs as a result of a chemical reaction. A chemical change always produces one or more types of matter that differ from the matter present before the change. |
How does a mixture differ from a pure substance?
Select the correct answer below:
pure substances are easily separated into components, mixtures are not
mixtures all have uniform compositions, pure substances do not
pure substances have constant chemical and physical properties while mixtures are varied
mixtures require chemical methods of separation while pure substances can be separated by physical means | Correct answer:
pure substances have constant chemical and physical properties while mixtures are varied
Mixtures can be classified as homogenous or heterogenous and can be separated into their component parts by chemical or physical means. Pure substances have constant chemical and physical properties while mixtures can be varied. |
Which of the following is NOT a physical property of a piece of paper?
Select the correct answer below:
the shape of the paper
the color of the paper
that it burns readily
that it can be readily crumpled up | Correct answer:
that it burns readily
Burning is a combustion reaction, in which chemistry is occurring, so the ability of paper to burn is an example of a chemical property. |
Which of the following can be broken down into elements by chemical means?
Select the correct answer below:
an element
an atom
a compound
a mixture | Correct answer:
a compound
A compound can be broken down into two or more elements by chemical means. An element and atom are already in their most simple forms and cannot be broken down further. A mixture can be separated by physical changes rather than chemical. |
The image below was captured over a hot mug of coffee on a cold morning. Which state of matter is present in the image?
An image of a curling stream of greyish blue steam, like the steam from a cup of coffee, is shown.
Select the correct answer below:
solid
liquid
gas | Correct answer:
gas
The image shows gas or steam rising off a hot mug of coffee. These particles have little or no attraction to each other; thus they spread themselves out as much as possible to fill the space around them. |
In order to identify a chemical property of matter, one thing scientists might look for is:
Select the correct answer below:
a change in shape of the substance.
a change in state of matter.
the formation of a precipitate.
the freezing of a substance | Correct answer:
the formation of a precipitate.
In order to identify a chemical property for a type matter, scientists look for a chemical change, such as the formation of a precipitate during a reaction. |
All of the following are considered pure substances, EXCEPT:
Select the correct answer below:
water
gold
silver
soil | Correct answer:
soil
Soil is not considered a pure substance. A pure substance is a homogeneous substance that has a constant composition. The composition of soil varies from sample to sample. |
A __________ contains more than one type of substance as part of its composition.
Select the correct answer below:
mixture
pure substance
compound
element | Correct answer:
mixture
A mixture contains more than one type of element or compound. A mixture can be categorized as homogeneous or heterogeneous depending on whether it has a uniform composition or not. |
Which of the following is a physical property?
Select the correct answer below:
acidity
color
flammability
corrosiveness | Correct answer:
color
Color is a physical property, whereas acidity, flammability, and corrosiveness are all chemical properties. |
A(n) _______ is a substance with a fixed composition of atoms of two or more different elements that are bonded together.
Select the correct answer below:
mixture
compound
solution
element | Correct answer:
compound
A compound is a substance with a fixed composition of atoms of two or more different elements that are bound together. For example, water is a substance composed of two different elements, hydrogen and oxygen, where there is a 2:1 ratio of hydrogen atoms to oxygen atoms. Therefore, water or H2O is a compound. |
Which of the following states of matter can exert pressure?
Select the correct answer below:
solid
liquid
gas
all of the above | Correct answer:
all of the above
All the phases of matter can exert pressure. |
Which of the following could be considered a chemical change?
Select the correct answer below:
dew condensing on a leaf
mixing sugar in with your tea
coal burning
water evaporating from a pond on a hot day | Correct answer:
coal burning
Phase changes and mixing of substances are physical processes. When coal burns, carbon atoms form new chemical bonds to oxygen atoms, which is a chemical process. |
Which of the following is an example of a heterogenous mixture?
Select the correct answer below:
gasoline
air
a sports drink
salad dressing | Correct answer:
salad dressing
Salad dressing is an example of a heterogenous mixture as it has a varied composition throughout. The remaining choices are homogeneous mixtures as taking any sample of them would result in a uniform composition from each sample. |
Which of the following is a physical change?
Select all that apply:
chopping wood
bending metal
cutting a cake
frying an egg | Correct answer:
chopping wood
bending metal
cutting a cake
Chopping wood, bending metal, and cutting a cake are all physical changes because the composition of the material isn't chemically changing. Frying an egg changes the chemical composition of the egg and is therefore a chemical reaction. |
A molecule comprised of more than one type of atom is called a(n):
Select the correct answer below:
compound
mixture
element
reactant | Correct answer:
compound
A mixture is composed of two or more types of matter and can be separated by physical changes. Elements are pure substances that cannot be broken down into simpler substances by chemical changes. And reactants are substances undergoing reaction. |
Which of the following is an example of a homogenous mixture?
Select the correct answer below:
oil and vinegar salad dressing
chocolate chip cookie
soil
maple syrup | Correct answer:
maple syrup
Maple syrup is an example of a homogenous mixture. Salad dressing, chocolate chip cookies, and soil are all examples of heterogeneous mixtures. |
What physical state of matter is associated the particles having least amount of thermal energy?
Select the correct answer below:
gas
solid
liquid
All phases of matter contain the same measure of thermal energy. | Correct answer:
solid
Solids have the most rigidly packed particles (molecules, ions, or atoms) because they have the lowest amount of thermal energy compared to the other states of matter for that substance. |
A large change in temperature (not resulting from external heating) with the appearance of gas bubbles is most likely an indication of:
Select the correct answer below:
a chemical change
only physical changes occurring
molecules are undergoing physical changes
none of the above | Correct answer:
a chemical change
A large change in temperature with the appearance of gas bubbles indicates that a chemical change has most likely occurred. |
What can be observed without changing the composition of matter?
Select the correct answer below:
flammability
reactivity
boiling point
toxicity | Correct answer:
boiling point
A physical property can be observed without changing the composition of matter. Flammability, toxicity, and reactivity are all chemical properties, whereas boiling point is a physical property. |
Homogeneous Mixture Definition | A homogeneous mixture is a mixture of substances blended so thoroughly that you cannot see individual substances. Every sample of the mixture will show the same amounts of each substance. Homogeneous mixtures can be solid, liquid, gas, or plasma mixtures.
Properties Of Homogeneous Mixtures
Homogeneous mixtures have several identifying properties:
Homogeneous mixtures that are thoroughly mixed down to the level of molecules are called solutions.
Homogeneous mixtures exist in one phase of matter at a time. You will not see liquid water and solid water together in a homogeneous mixture. That means your glass of ice water, with ice cubes floating in it, is a heterogeneous mixture of homogeneous mixtures.
Homogeneous mixtures cannot be expressed as chemical formulas.
To describe any homogeneous mixture accurately, you need to name the components and tell their proportion or ratio within the mixture.
Like all mixtures, homogeneous mixtures can be separated into their components, usually by taking advantage of their physical properties such as boiling point or magnetism.
Saltwater is an example of a homogeneous mixture that can be easily separated by evaporation. |
| A heterogeneous mixture is a mixture with a non-uniform composition. The composition varies from one region to another with at least two phases that remain separate from each other, with clearly identifiable properties. If you examine a sample of a heterogeneous mixture, you can see the separate components.
In physical chemistry and materials science, the definition of a heterogeneous mixture is somewhat different. Here, a homogeneous mixture is one in which all components are in a single phase, while a heterogeneous mixture contains components in different phases.
Examples of Heterogeneous Mixtures
Concrete is a heterogeneous mixture of an aggregate: cement, and water.
Sugar and sand form a heterogeneous mixture. If you look closely, you can identify tiny sugar crystals and particles of sand.
Ice cubes in cola form a heterogeneous mixture. The ice and soda are in two distinct phases of matter (solid and liquid).
Salt and pepper form a heterogeneous mixture.
Chocolate chip cookies are a heterogeneous mixture. If you take a bite from a cookie, you may not get the same number of chips as you get in another bite.
Soda is considered a heterogeneous mixture. It contains water, sugar, and carbon dioxide, which forms bubbles. While the sugar, water, and flavorings may form a chemical solution, the carbon dioxide bubbles are not uniformly distributed throughout the liquid. |