A sample of ammonia has a mass of 51 g. How many molecules are in this sample?

2. A transformer only works with which type of current? A direct 70% B split Sm 70% C alternating D magnetic

Minnesota is farther from the equator then Florida. That means the climate in Minnesota is probably A drier B hotter C colder D wetter

a speed bump is a raised ridge that runs across the surface of a street, a parking lot, or driveway. What is the purpose of a speed bump, and how is it similar to activation energy?

What is the symbol for the element whose atoms have 40 electrons each?

Which is a characteristic of a decomposition reaction? A. Substance P replaces X in the compound XY. B. Substance XYZ breaks down into X, Y, and Z. C. Substance Z burns in the presence of oxygen to form ZO. D.

Butter is melted in a pan. Which of the following is true about the change? Select one: a. It is a physical change that absorbs energy. b. It is a physical change that releases energy. c.

The freons are a class of compounds containing carbon, chlorine, and fluorine. while they have many valuable uses, they have been shown to be responsible for depletion of the ozone in the upper atmosphere.

Write its complete chemical symbol including mass number, atomic number, and net charge (if any).

How would you be able to use the spectrum of each gas to establish its identity

Which does not add to the reliability of a scientific source of information? displaying data in a colored chart clearly identifying the sources of the data explaining how the data was collected showing that many scientists had reviewed the