An element has atomic number 10 and an atomic mass of 20. How many neutrons are in the atom of this element?

An original sample of the radioisotope fluorine-21 had a mass of 80.0 milligrams. Only 20.0 milligrams of this original sample remain unchanged after 8.32 seconds. What is the half-life of fluorine-21? (1) 1.04 s (3) 4.16 s (2) 2.08 s (4) 8.32 s

An example of something that stores chemical energy is

A community needs more electrical energy. The community is located in an area with the following characteristics: • Average wind speed of 5 to 10 mph • One small river with slow currents • Dry, sunny conditions most of the year • No coal or oil

Create a top 10 list on the why they should teach science

Heating galactose, a monosaccharide sugar, in the presence of excess oxygen produces carbon dioxide gas and water vapor. Classify this reaction. C6H1206 (s) + 602 (9) - 6C02 (0) + 6H20 (9)

A balloon contains 1.00 mol helium gas at STP. What will the volume of the balloon be if the pressure increases to 2.00 atm?

If 100 mL of a gas were enclosed in a buret at 500 mm Hg, what volume would the gas occupy at 1000 mm Hg at the same temperature? P1V1=P2V2

Would Mn (HPO4) 2 be manganese (II) monohydrogen phosphate?

The fundamental frequency of a violin string is 440 hz. the frequency of its second harmonic is

How much of a 15.0M stock solution do you need to prepare 250ml of a 2.35ml hf solution?