How many moles of helium gas are contained in 4.0: flask at STP

Which best describes a mixture? It has a single composition, and it has a set of characteristics that does not change. It can have different compositions, but it has a set of characteristics that does not change.

Explain why the chemical formula for calcium hydroxide, Ca (OH) 2 is not written as CaO2H2

What state has similur soil composition and structer to michigan?

Examine the three isotopes of potassium (K) below. potassium-41, potassium-39, potassium-40 Which answer choice lists these isotopes in the order of having the least amount of neutrons to having the most amount of neutrons?

Electric charge is what? A. Kinetic Energy B. Radiation C. Discovery D. Electricity

Which of these is a chemical property? A. Mercury is a dense liquid. B. Iodine vapor has a purple color. C. Aluminum is a very conductive metal. D. Ice melts at 0°C. E. Iron rusts in wet weather.

Which of the following is not true about the importance of the carbon cycle to living things? a. Plants use carbon dioxide to make energy. b. Carbon is the second most abundant molecule in organisms. c.

Fruit flies can either have a brown body or a black body. The allele for a brown body (B) is dominant to the allele for a black body (b). A brown fruit fly was crossed with a black fruit fly as shown below.

A light-year measures the distance a light beam can travel in one year. One light-year is equal to 9 500 000 000 000 kilometers.

The first ionization energy, e, of a potassium atom is 0.696 aj. what is the wavelength of light, in nm, that is just sufficient to ionize a potassium atom? values for constants can be found here.