Milk of magnesia, a suspension of Mg(OH)2 in water, reacts with stomach acid (HCl) in a neutralization reaction. Mg(OH)2(s) + 2 HCl(aq) −→ 2 H2O(ℓ) + MgCl2(aq)

Question

a) What mass of MgCl2 will be produced if 6.99 g of Mg(OH)2 reacts? Answer in units of g.

b) What mass of HCl is required to completely react with 6.99 g of Mg(OH)2? Answer in units of g.

Answer 1

You have the balanced equation so that is a good start. The balanced equation coefficients tell you the moles of each. 1 Mg(OH)2=2 HCl=2 H2O=1 MgCl2.

the first step,is to convert the grams of Mg(OH)2 to moles.

Grams x 1 mol/molecular mass g. 6.99 g Mg(OH)2 x 1 mol/ ___ g. = ____ mol Mg(OH)2

See how the grams will cancel leaving moles.

__ moles Mg(OH)2 x (1 mol MgCl2/1 mol Mg(OH)2) This is from the balanced equation.

the HCl part would be solved by using the conversion of (2 mol HCl/1 mol Mg(OH)2) instead Again from the balanced equation. Then convert moles to grams

Answer 2

C'mon Hilary, that's 5 questions on the same material. Balance the equation first, convert any dayta to moles, carry reactants through to products per the stoichiometry, convert back to mass units etc. as needed.

Any further questions, would be spamming!

-- Mr. d.