Exam 3: Elements of Chemistry

Each night you measure your height just before going to bed. When you arise each morning, you measure your height again and consistently find that you are 1 inch taller than you were the night before but only as tall as you were 24 hours ago! Is what happens to your body in this instance best described as a physical change or a chemical change?

Which of the following is an example of a chemical change?

The element silicon has a melting point of 1,410°C and a boiling point of 2,355°C. It is a weak conductor of electricity, its density is 2.3 grams per cubic centimeter and it easily forms silicon dioxide when exposed to air. Which of the following is a chemical property of silicon?

How might you separate a mixture of sand and salt?

The following image describes which type of change?

A chemical reaction is synonymous to a ________.

Oxygen, , is certainly good for you. Does it follow that if small amounts of oxygen are good for you then large amounts of oxygen would be especially good for you?

Which of the following physical properties would you expect for krypton (Kr)?

What chemical change occurs when a wax candle burns?

A combination of two or more substances in which they no longer retain their chemical properties is called a(n) ________.

What is the name of the following compound? NaF

The boiling point of methanol is 65°C and the boiling point of ethanol is 78°C. Which of the following statements is true?

Strontium, Sr (number 38), is especially dangerous to humans because it tends to accumulate in calcium-dependent bone marrow tissues (calcium, Ca, number 20). This fact relates to the organization of the periodic table in that strontium and calcium are both ________.

In the winter Vermonters make a tasty treat called "sugar on snow" in which they pour boiled-down maple syrup onto a scoop of clean fresh snow. As the syrup hits the snow it forms a delicious taffy. Which of the following changes are involved in the making of sugar on snow?

Which of the following would be considered a physical property?

Some products on the market today involving nanotechnology include ________.

Which atom is smallest?

Helium, He, is a nonmetallic gas and the second element in the periodic table. Rather than being placed adjacent to hydrogen, H, however, helium is placed on the far right of the table because ________.

Which of the following would not be considered a chemical property?

The systematic names for water, ammonia, and methane are dihydrogen monoxide, O; trihydrogen nitride, N ; and tetrahydrogen carbide, C . Why do most people, including chemists, prefer to use the common names for these compounds?