One of the most difficult solar energy design problems to solve is:

A. how to collect the sunlight

B. how to transform sunlight into heat

C. storing the heat energy

D. difficulty in using the energy

Consider the half reaction below. Upper C u superscript 2 plus (a q) plus 2 e superscript minus right arrow upper C u (s). Which statement best describes what is taking place? Copper is being oxidized. Copper is being reduced.

The volume of 0.05 M H2SO4 is needed to completely neutralise 15ml of 0.1 M NaOH solution is

Caclulate the pH of a solution with a hydrogen ion concentration of 1X10-7

Ions are atoms that have gained or lost which subatomic particles? A. protons B. neutrons C. electrons

Al (s) + hcl (aq) → alcl3 (aq) + h2 (g). assume you have plenty of hcl and 6.0 mol of al. how many moles of h2 are formed?

A 75.00 g a sample of a substance is analyzed and found to consist of 32.73 g phosphorus and 42.7 g oxygen. calculate the percent composition of this substance.

Which one of the following melts the fastest: rectangular prism, cylinder, and rectangular trapezoidal trough?

A 1.8-mL volume of seawater contains about 4.0 * 10^-10 g of gold. The total volume of ocean water is about 1.5 * 10^21 L. Calculate the total worth of all the gold in the world's oceans if the price of gold is $19.

Why are numbers placed before the elements and molecules in a chemical equation?

Which of these pairs of elements have the same number of valence electrons? oxygen (O) and bromine (Br) selenium (Se) and bromine (Br) carbon (C) and lead (Pb) oxygen (O) and carbon (C) sodium (Na) and magnesium (Mg)