Question

A metal reacts with concentrated hydrochloric acid (12 M HCl) to give the soluble metal hexachloride based on the following reaction:

M (s) + 6 HCl (aq) → MCl6 (aq) + 3 H2 (g)

If it takes 23 mL of concentrated hydrochloric acid to fully dissolve 8.5 g of the metal, what is the identity of the metal?

Give the answer as the chemical symbol:

0.35 L of a P4 solution with a concentration of 0.70 M and 2.5 L of a Br2 solution with a concentration of 0.39 M react completely when mixed to give a single product. What is the product of the reaction?

A. PBr

B. PBr3

C. PBr5

D. P2Br4

E. P2Br8

A 5.00 g block of strontium metal (Sr) sits in 0.275 L of water.

Over time, oxygen gas (O2) in the water reacts with the metal to give strontium oxide. If the oxygen gas concentration in the water is 0.050 M, how many grams of the strontium metal will remain when all of the oxygen has reacted?

Answer 1

#

no. of mole = molarity X volume of solution in liter

23 ml = 0.023 liter

no. of mole HCl = 12 X 0.023 = 0.276 mole

According to reaction 6 mole of HCl react with 1 mole of metal M then to react with 0.276 mole of HCl requied mole of metal = 0.276 X 1 / 6 = 0.046 mole of metal

metal weight is 8.5 gm

thus 0.046 gm of metal = 8.5 gm then 1 mole of metal = 1 X 8.5 / 0.046 = 184.78 gm

molar mass of metal = 184.78 gm / mole

tungsten (W) have atomic weight = 183.84 gm is near about given calculated weight therefore identity of given metal is

tungsten (W)