What do scientists think life developed from?

a.

simple chemicals

c.

photosynthesis

b.

oxygen

d.

a nucleus

Which is an example of the flow of heat through conduction? Hot air rises to the top of the room A hot-air balloon rises into the sky Heat flows from a hot liquid to a pot handle Heat causes winds to blow from the water to the land

Differentiate between boiling and evaporation.

Every reduction reaction MUST be accompanied by A) an oxidation reaction. B) formation of covalent bonds. C) formation of ionic bonds. D) formation of water.

How many moles of boron are in 1.61 * 1034?

A hydrate of beryllium nitrate has the following formula: Be (NO3) 2 - x H2O. The water in a 3.41-g sample of the hydrate was driven off by heating. The remaining sample had a mass of 2.43 g. Find the number of waters of hydration (x) in the hydrate.

Nitrous oxide (n2o), or laughing gas, is commonly used as an anesthetic in dentistry and surgery. how many moles are present in 8.4 liters of nitrous oxide at stp?

How can an atom be electrically neutral when it contains particles that are charged?

Is boiling water considered physical or chemical bond

Which of the following is the correct scientific notation for 0.000451 g? 4.5 x 10-3 4.5 x 10-5 4.51 x 10-4 45.1 x 10-4

A phase change from a solid to a gas is called what