Elements, Compounds and Mixtures

Which of the following is not an element?

• Helium

• Nitrogen

• Water

• Sodium

The second-most abundant element in Earth's crust is silicon, which is-

• an impure substance with the symbol Sc

• a pure substance with the symbol Sn

• an impure substance with the symbol S

• a pure substance with the symbol Si

Which of the following are considered pure substances

• element

• Compound

• Mixture

• None

Mary's mother has a perfect diamond she wants to put into a necklace setting. If diamonds are made of only carbon, then what can Mary determine?

• a diamond is a pure substance that can be represented only by the chemical symbol C

• a diamond is an impure substance that cannot be represented by a single chemical symbol

• a diamond is a pure substance that can be represented only by the symbol Ca

• a diamond is an impure substance that can be represented by the chemical symbol Do

A malleable sheet of metal used to wrap food in the kitchen is made of only aluminum. What can be said about the metal sheet?

• it is an impure substance, represented by the symbol Al

• it is a pure substance, represented by the symbol A

• it is an impure substance, represented by the symbol Au

• it is a pure substance, represented by the symbol Al

Sam's mother is cooking breakfast in a cast iron frying pan. If the pan is made only of iron, what can Sam conclude?

• Iron is a pure substance with the chemical symbol I

• Iron is a pure substance with the symbol Fe

• Iron is a pure substance with the chemical FE

• Iron is a pure substance with the chemical symbol F

Pure substances are composed of only one type of atoms are-

• compounds and can be represented by two or more chemical symbols

• mixtures and can be represented by two or more chemical symbols

• alloys and can be represented by one chemical symbol

• elements and can be represented by one chemical symbol

How are compounds formed?

• when two elements in the same state come into contact

• when atoms from two or more elements chemically bond

• when pure elements are broken down into their basic parts

• when two or more atoms from the same element physically bond

What elements are represented in CHONPS? (use the periodic table)

• Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus and Sulfur

• Carbon, Helium, Nitrogen, Oxygen, Phosphorus and Sulfur

• Chromium, Hydrogen, Oxygen, Phosphorus and selenium

• Calcium, Hydrogen, Nitrogen, Oxygen, Potassium and Sulfur

Which of the following is an element?

• Oxygen

• Salt

• Vinegar

• Water