Why must sample spots be above the solvent in paper chromatography

16. The three major types of volcanoes are

A metal ice-cube tray and a plastic tub of ice cream are sitting in the freezer. Why does the ice-cube tray feel colder to touch than the tub of ice cream? A. The metal ice cube tray has a lower latent heat of fusion. B.

Sometimes manufacturers do not want heat to be conducted through certain parts, such as the handles of pots, the steering wheels in cars, and swings on playgrounds. What material are these parts likely to be made out of?

Do you think thar solids can undergo convection? Explain.

What volume of water would be added to 16.5 ml of a 0.0813 m solution of sodium borate in order to get a 0.0200 m s?

Name 4 common chemical properties of matter

Why is photosynthesis so important to plants, and can't animals use it?

One way the government of Kim Jong-il controls the lives of the people who live in North Korea is by a. requiring every citizen to vote. b. controlling information its people receive from the outside world. c. enforcing free trade with other nations.

Give reasons 1) copper utensils and sheets become blackish after some days

Predict the spontaneity of a reaction (and the temperature dependence of the spontaneity) for each possible combination of signs for? H and? S (for the system).