Matter: Introduction to Matter

Which term can be used to best describe ammonia ?

• Element

• Compound

• Molecule

• Ammonia is a compound and a molecule because it has two different types of atoms. For the same reason, it is not an element.

Tags

NGSS.MS-PS1-1

A classmate examines a substance that conducts electricity and is shiny but has no color. He says that it must be silver. What is this classmate's error?

• Conductivity and a silvery appearance are properties of other metals, such as iron or aluminum. The classmate can't be sure that they have silver, or even that it is a pure substance.

• There is no error. It's shiny and conductive. It must be silver.

A classmate says that a molecule and a compound are the same thing, because all compounds are molecules. Is he correct?

• Yes

• No, because a molecule is a group of two or more atoms held together by chemical bonds, but not necessarily different types of atoms. A compound is a group of atoms of different elements. In other words, all compounds are molecules, but not all molecules are compounds...

Tags

NGSS.MS-PS1-1

Think about different mixtures in your kitchen. Which of the following is an example of a homogenous mixture?

• Chunky Salsa

• Honey

Think about different mixtures in your kitchen. Which of the following is an example of a heterogenous mixture?

• Chunky salsa

• Honey

Which is an example of a pure substance?

• Distilled water

• Orange juice

Tags

NGSS.MS-PS1-4

Which is an example of a mixture?

• DIstilled water

• Orange juice

A dental student needs to find the density of an intricately crafted crown (with a very irregular shape) in order to determine whether it is pure gold. The dental student knows how to determine the mass of the crown using a triple beam balance, but can't remember how to determine the volume of the unknown metal crown of irregular shape in order to determine the density (mass divided by volume). What is the most precise way to find the volume of this very irregularly shaped, intricately crafted crown?

• Calculate the volume using the formula base x width x height. The the ratio of mass to volume is density. The density of pure gold is 19.32 grams per cubic centimeter at 20 °C. If the calculated density equals this number, then the crown is pure gold.

• Use the volume displacement method to calculate volume: place the crown into a known volume of water and measure the total volume with the crown immersed. The difference between the total volume and original volume is the crown's volume. The the ratio of mass to volume is density. The density of pure gold is 19.32 grams per cubic centimeter at 20 °C. If the calculated density equals this number, then the crown is pure gold.

If the force of gravity on a planet is twice that of earth, what will a 45.3592 kilogram student who weighs 100 pounds on earth weigh on the above-mentioned planet?

• 100 pounds

• about 45 kilograms

• 200 pounds

• about 90 kilograms

• 50 pounds

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-4

If the force of gravity on a planet is twice that of earth, what is the mass of a 45.3592 kilogram student who weighs 100 pounds on earth weigh on the above-mentioned planet?

• 100 pounds

• about 45 kilograms

• 200 pounds

• about 90 kilograms

Tags

NGSS.MS-PS2-4