Which of these substances are compounds? How do you know?

A. Salt (NaCl)

B. Nitrogen (N)

C. Helium (He)

D. Water (H2O)

Whatis the SI unit used by chemists to measure the amount of an element or substance

Como um acido pode ser identificado? quais sao suas caracteristicas?

Which of the following is a compound machine? A. Bicycle B. Ramp C. Knife D. Screw

Sin^4x+2sin^2x-3=0 find interval [0,2pie)

Which of the compounds below are amines? 1. H4C-NH-CH3 2. H3C-NH-C-CH3 H2C-CH3 1 + H3C-CH2-N-CH3 CH3 N 3. H 4.

What are some catchy projects titles for the question, "What liquids cause the most tooth decay?"

Show that the speed of an electron in the nth bohr orbit of hydrogen is αc/n, where α is the fine structure constant. what would be the speed in a hydrogen-like atom with a nuclear charge of ze?

Most modern forms of transportation are powered by fossil fuels. Carbon dioxide, methane, carbon monoxide, and other gases are released into the atmosphere during the production and combustion of these fuels.

Does the reaction of a burning candle give off or absorb heat

1. Describe the difference between valence and core electrons.