What mineral is not scratched by a fingernail, but is scratched by a copper penny?

Why do you think DNA has had such an impact on forensic science

What is the mass of solute in 200.0 L of a 1.556-M solution of KBr

The procedure we used to make soap was developed in the early 1800s. Back then, most soap was very harsh on the skin, why do you think this was? What technology has significantly improved since then in order to minimize this harshness?

Which one of these examples shows a homogeneous mixture? oil and vinegar or salt water

Explain why different liquids boil at the different temperatures

Calculate the volume of a 0.323-mol sample of a gas at 265 K and 0.900 atm.

What is the molar mass of the following substance : Cs2CO3

What does the velocity of a wave describe

Sulfur (S) has 16 protons and 16 neutrons. How many electron shells does an element of sulfur have?

Which one of the following statements about orbital energies is incorrect? A) The energy of a given orbital increases as the nuclear charge Z increases. B) In many-electron atoms the energy of an orbital depends on both n and l.