This is how zirconium appears in the periodic table. A purple box has Z r at the center and 40 above. Below it says zirconium and below that 91.22.

Rounded to the nearest whole number, how many electrons are in an atom of zirconium?

40
51
91
131

Given sno2 + 2h2 - sn + 2h20 tin oxide reacts with hydrogen to produce tin and water. how many moles of sno2 are needed to produce 500.0 grams of sn?

Fossil fuels are organic compounds that are made from

Which statement is true about a catalyst? a: a catalyst decreases the rate of the reaction. b. a catalyst is consumed during a chemical reaction. c. a catalyst lowers the activation energy of a reaction. d. a catalyst increases the reactant concentration during a reaction.