there are 25 elements found in living things. how many of these elements are found in some organisms but not at all?

Ms. Block's students are studying chemical reactions. A classic reaction occurs when a metal is added to hydrochloric acid.

What is the catalyst defined as

Select the single best answer. Consider the following half-reactions: MnO4 - (aq) + 8H + (aq) + 5e-→ Mn2 + (aq) + 4H2O (l) NO3 - (aq) + 4H + (aq) + 3e - → NO (g) + 2H2O (l) Will NO3 - oxidize Mn2 + to MnO4 - under standard-state conditions?

Why graphite can rub off the pencil onto the paper

What is the net ionic equation for the reaction of solid iron with aqueous copper sulfate?

You are about to open a container of soy milk but notice that there are instructions to "shake well before serving." the soy milk is most likely a

Give reason: a. Fractionating columns with beads are used for fractional distillation b. Crystallisation is a better technique than evaporation

How can a gardener remedy soil that is overly acidic?

True or false everything has the same amount of energy?

4NH3 (g) + 502 (g) - >6H20g) + 4NOg) What is the enthalpy change for this reaction?