Mg(s) + 2 HCl(aq) −−−→ MgCl2aq) + H2(g)   given that the mass of magnesium is 0.030 g, find the moles of H2.

What is the formula (solve for x) for the original hydrated sample of copper (II) sulphate? You weigh a sample of CuSO4 · XH2O. After you heat the sample, you find that the mass of the anhydrous salt is 1.47g. What is the value of x? CONTEXT Mass of just anhydrous compound = mass of anhydrous compound rod mass of beaker and 108.34g - 106.87g = 1.47g %3D %3D = original compound mass - anhydrous compound mass = 3.00g - 1.47g = 1.53g Mass of just water

How many moles of Al are necessary to form 71.2 g of AIBR, from this reaction: 3 2 Al(s) + 3 Br,(1) → 2 AIB.,(s) ?

3cucl, (aq) + 2Fe(s) 2Fecl,(aq) • + 3Cu(s) If you had a solution of copper(II) chloride that contained 33.1 g of CuCl, and then added 11.15 g of iron, how much solid copper would you get (assume 10% yield)?

You have 235.5 g of Ba(OH)2   How many moles of barium hydroxide, Ba(OH)2, are present in 235.5  g? How many moles of barium ions are present? How many moles of hydroxide ions are present?

Consider the following chemical reaction: CaO(s) + H2O(l) ----------> Ca(OH)2 (aq) if 1.00 g calcium oxide is mixed with 2.00 g water, calculate grams of the product. CaO = 56.08 g/mole,  H2O = 18.02 g/mole,  Ca(OH)2 = 74.10 g/ mole

A chemist adds 2.00 L of a 5.9 × 10M mercury(II) iodide (HgI₂) solution to a reaction flask. Calculate the moles of mercury(II) iodide the chemist has added to the flask. Round your answer to 2 significant digits. mol 0 X S

Without doing any detailed calculations (but using a periodic table to give atomic weights), rank the following samples in order of decreasing number of atoms: 0.50 mol H2O, 23g Na, 6.0 × 10^23 N2 molecules.   How do I do this?

An individual has 7.5 × 10−3 mol of hemoglobin (molar mass = 64,456 g/mol) in their blood. How many hemoglobin molecules is this?

A mass of 2.50 g of hydrated copper (II) sulfate is placed in a crucible and heated. On heating, 1.59 g of white anhydrous copper (II) sulfate is left behind. Determine the percentage of water in copper (II) sulfate.