If my problem statement is: Which mask filters air more effectively?

And my independent variable is: Type of mask

What's my dependent variable?

In the 1800s, one of the statements in john dalton's atomic theory was that atoms are indivisible. later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. what happened to the indivisible atom part of dalton's atomic theory, and why?

Some molecular compounds, such as hcl, ionize completely in solution. for molecular compounds such as h2co3, most molecules do not ionize in solution. which describes the properties of these two solutes? a. hcl and h2co3 have the same effect on the properties of the solution. b. hcl raises the freezing point of water more than h2co3 does. c. hcl raises the boiling point of water more than h2co3 does.

Determine type of reaction & predict the product c3h12+o2 =