What approximate percentage of the Earth's freshwater is groundwater?

a.

10%

b.

20%

c.

30%

d.

40%

Do all metal produce electromagnetic radiation when they are heated in a flame

Which of the following is most clearly a benefit of genetic engineering? A. transfer of modified genes from a modified corn plant to a nearby standard corn plant B. appearance of early onset arthritis in a genetically modified sheep C.

A mixture of 50.0ml of ammonia gas and 60.0ml of oxygen gas reacts. If all the gases are at the same temperature and pressure, and the reaction continues till one of the gases is completely consumed.

What type of reaction is Zn + CuCl2 → Cu + ZnCl2? O A. Decomposition O O O B. Double-replacement c. Synthesis D. Single-replacement

identify the element in period 3 that requires the least amount of energy to remove the most loosely held electrons from a mole of gaseous atoms of the element in the ground state.

Model describe how you would show j. j. thomson's model of the atom using small beads and clay

Switching one substance for another is called ... ? a) displacement b) synthesis c) decomposition d) oxidation

C2h4 + O2 - CO2 + H2O If we start with 20 grams of CH4, how many moles of CO2 will form?

How does chemical energy relate to the atom and how can we use it?

A positively charged atom is known as a cation. A cation will? ... A) have more protons B) have to same number of protons and electrons. C) Be the same as a neutral atom. D) have more electrons.