What are the five main spheres of the earths system

120 students took a chemistry test. 22 scored a 90.55 scored an 80, 12 scored a 70, 11 scored a 60, and 20 scored a 50. Calculate the weighted average of the test scores.

Hydrogen sulfide decomposes according to the following reaction, 2 H2S (g) → 2 H2 (g) + S2 (g) where ∆S = + 78.1 J/K, ∆H = + 169.4 kJ, which answer describes the entire range of temperatures where the reaction would be spontaneous?

If the temperature of a weather balloon is increased how does the volume of the balloon change

Which element has the greatest density at STP? (1) scandium (3) silicon (2) selenium (4) sodium

A mineral sample scratches fingernails, pennies, and glass but does not scratch steel as shown below. what is the hardness of the mineral?

A 55.3 g sample of lead heated and then quenched in a 175g sample of water. During the quenching reaction the temperature of the water increases from room temperature, 25.0 °C, to 42.6 °C.

What conclusion can you draw from this experiment about the components of the black ink

How does the size of ions affect the conductivity of a solution?

How to write complete ionic and net ionic equations?

chromium can combine with chlorine to from corneum chloride which equation is a correct representation of this reaction