Why is electron affinity positive when the second electron is added to oxygen

Why do we call water the univeral salivnet

How many atoms are in 5.7 moles of copper atoms?

What is the final volume of a gas that initially occupies 2.50 l at and is subsequently heated to?

A student is given a mixture that he is told consists of two pure substances. the mixture is a clear liquid. the student is able to seperate the mixture only through distilation.

The diagram shows molecules in a fluid. Explain the sequence of events that happens when this fluid cools down. Be sure to focus on what happens to the molecules and to the fluid in general. Five events should be included in your answer.

What will most likely happen when a warmer air mass exists above a polar ice sheet? The temperature of the ice sheet will be lowered. Heat will be transferred from the air mass to the ice. The air mass will exert high pressure and rise upwards.

A 2.00 L sample of gas at 35 C is to be heated at constant pressure until it reaches a volume of 5.25 L. To what Kelvin temperature must this sample be heated?

Of the following reactions, which one produces oxygen gas? Fermentation Anaerobic respiration Aerobic respiration Photosynthesis

Describe the electrodes in this iron-copper galvanic cell.

What happens to wood when it burns?