When adding and subtracting, the answer must have the same number of digits to the right of the decimal as the original number value having the fewest number of digits to the right of the decimal point. Add and subtract as indicated. Round off when necessary.

1) (4.32x10^3cm)-(1.6x10^4mm)

2) (2.12x10^7mm)+(1.8x10^3cm)

please help :(

Becquerel expected to find ( he developed the photographic plate that had sun-exposed minerals on top of it. becquerel expected to find ( he developed the photographic plate that had been in the closed drawer.

What is the mass of 0.46 mol of mgcl2

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.)