should I go ahead and complete the last assignment of the 9th grade? I got a week till I have to turn it in. I can complete it in about an hour. What do yall think?

Which is true of chemicals? a. things containing chemicals always cost a lot of money. b. chemicals are never dangerous. c. chemicals are in many substances in a home. d. chemicals are rarely found on earth.

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

Read the chemical equation. 2c2h2 + 5o2 → 4co2 + 2h2o which of the following statements would be correct if one mole of c2h2 was used in this reaction? one mole of oxygen was used in this reaction. five moles of oxygen were used in this reaction. four moles of carbon dioxide were produced from this reaction. two moles of carbon dioxide were produced from this reaction.