A sample of phosphorus-32 has a half-life of 14.28 days. If 55 g of this radioisotope remain unchanged after approximately 57 days, what was the mass of the original sample?

From what names do some chemical symbols come from

Which combination of atoms can form a polar covalent bond?

The density of water is 1.00 g/mL. If you're swimming pool holds 208,000 gallons of water, what is the weight of the water in a field swimming pool in tons? (1 ton = 2000lb).

Select true or false: if the ph of pure water is 7.0, the hydroxide ion concentration in pure water is 1 * 10-7 m.

Why do Beryllium and fluorine combine in a 1:2 ratio?

Benzene, C6H8, has an enthalpy of fusion = 10.19 kJ/mol. Calculate the amount of energy which is needed to change 88.0 g of solid benzene at 5.53°C into liquid benzene, also at 5.53°C?

What is the H3O + ion concentration of a solution that has an OH - ion concentration of 1.0 * 10^-3M? A) 1.0 * 10^-3M B) 1.0 * 10^-7M C) 1.0 * 10^-11M D) 1.0 * 10^-14M

Given the following chemical reaction: 2 O2 + CH4 CO2 + 2 H2O In the reaction of 6 moles of CH4 with excess oxygen, how many moles of water could be produced? 6 C 12.01 Carbon 1 H 1.01 Hydrogen 8 O 16.00 Oxygen A. 4 B. 6 C. 8 D. 12

Most mutagens have what kind of an effect on an organism?

According to the hess's law, the enthalpy of solution is: δhsoln = δhsolute + δhsolvent + δhmix. considering dissolving a small drop of nonpolar pentane oil in water which term (s) in the equation will experience the largest enthalpy change.