Cadavz

You're given the area (100 mi^2) and the thickness (25ft). A few things to keep in mind: Volume = area * thickness 1mL = 1 cm^3 Density = mass/volume Thus, you have the volume and the density of mercury in the lake (which is .40 ug/mL). Inconveniently, yo...

Molecular formula for water: H2O Molecular formula for ammonia: NH3 1 H2O molecule has 2 H atoms 1 NH3 molecule has 3 H atoms 3.50 * 10^25 H2O molecules * 2 H atoms/H20 molecule = 7 * 10^25 H atoms for the water part of the solution 5.00 * 10^24 NH3 molec...

1mol of any substance = 6.022 * 10^23 elementary entities of that substance (be it atoms, molecules or whatever. Think of it as the chemist's "dozen" only it's 6.022 * 10^23 rather than 12.) For finding the amount of grams in 1 mol of an element, find the...

Erm, *atomic mass, sorry.

Total number of coins = 25 Number of dimes = x Number of quarters = 25 - x Value of 1 dime = .10 Value of 1 quarter = .25 Total value of coins = $3.55 The equation: .10(x) + .25(25 - x) = 3.55 .10x + 6.25 - .25x = 3.55 -.15x + 6.25 = 3.55 -.15x = -2.7 x =...

While dams can cause floods, I think the answer here would be C) a reservoir. Dams are made to retain water/a reservoir of water.

Change the mixed number into an improper fraction: 8 * 6 + 3 = 51/6 Divide the numerator by the denominator to get it in decimal notation. 51/6 = 8.5

Oh darn it, I forgot about simplification (still get a correct answer, but you work with larger numbers if you don't simplify).

Density = mass/volume mass = volume * density volume = mass/density You were given both the volume and density of ethyl alcohol, and you're looking for the amount the mass of ethyl alcohol added to the graduated cylinder. So, plug in the numbers for mass:...

When you have an element with different ions, you have to specify with Roman numerals which ion you're using when naming it. Copper has multiple charges, so you will have to specify which ion of copper you're using: Cu^+ is copper(I) and Cu^2+ is copper(I...

All right, you've got the radius of an atom. Whenever you get a problem asking for the volume, density, etc. you assume the atom is a sphere. The diameter of a barium atom would then be: 217pm * 2 = 434pm Either convert 4.33mm to pm or 434pm to mm. I'll c...

Find the equation: H2 + O2 --> H2O Balance the equation: 2H2 + O2 --> 2H2O Find out how many moles of H2 and O2 you've got: 4.0g H2 * 1mol H2/2g = 2 mol H2 16g O2 * 1mol O2/32g = .5mol O2 Which one will be used up before the other (aka which one is the li...