Which of the following is an nonmetal?

A. He

B. Re

C. Cu

D. Hg

A student investigated the diffusion of ammonia gas, NH3, and hydrogen chloride gas, HCl. The damp red litmus paper for NH3 changed colour after 30 seconds. How long does it take for the damp blue litmus paper to change colour for HCl?

What's the formula for carbon monoxide

How many sides does a triangle have? I cant figure it out (;

Which scientist is credited with developing the first atomic theory

A bar of soap measures 8 cm by 5 cm by 2 cm. Its mass is 90g. Calculate its density and predict whether this soap will float.

Which statement describes the redox reaction that occurs when an object is electroplated? A. It is spontaneous and requires an electric current. B. It is spontaneous and produces an electric current. C.

How are electromagnetic different than all other waves

Find the ratio of speeds of an electron and a negative hydrogen ion (one having an extra electron) accelerated through the same voltage, assuming non-relativistic final speeds. Take the mass of the hydrogen ion to be 1.67*10^{-27} kg.

A type of rock that undergoes changes because of heat and pressure

How many milliliters of a 1.25 molar HCL solution would be needed to react completely with 60 g of calcium metal Ca+2HCl - - > CaCl2 + H2