If 0.10 mole of sio2 and 0.20 mole hf are combined in the reaction sio2 + 4hf => sif4 + 2h2o which of these statements is false? a. hf is the limiting reactant. b. some sio2 will be left over. c. the theoretical yield of sif4 is 0.10 mole. d. more hf would be needed to ensure that all the reactants are used up. e. the theoretical yield of h2o will be 0.10 mole.

C. The Theoretical yield of SiF4 is = 0.10

Explanation:

A. is TRUE

0.10 mol SiO2  * 4 mol HF/mol SiO2 = 0.40 mol HF which we do not have. Hence, HF is the limiting reagent

B. is TRUE

Some Sio2 will be left over is true since our limiting reagent is HF

C.  is FALSE

0.020 mol HF * 1 mol SiF4 produced/ 4 mol HF = 0.05 mol SiF4 produced

Since the mol of SiF4 produced by  the limiting reagent HF is given in the ratio of 1/4  it follows that 0.05 mol SiF4 will be produced and no 0.10 therefore statement is FALSE

D.  is TRUE

Since HF is the limiting reagent is True that more HF will be needed to react completely with HF (exactly 0.20 mol HF) .

E.  is TRUE

The theoreical yield of wate is  0.10 mol TRUE

0.05 mol SiO2 * 2 mol H2O/ mol SiO2 = 0.10 mol H2O

calculate how many grams of ammonia can be produced from 4.21 grams of

n2 + 3h2 = 2nh3

my answer:

25.0g n2 x (1 mol/ 28.0gn2) x (2 mol nh3/ 1 mol n2) x (17.0g nh3/ 1 molnh3) = 30.36g n2

25.0g h2 x (1 mol h2/ 2.00g h2) x (2 mol nh3/ 3 mol h2) x (17.0g nh3/ 1 mol nh3) = 141.67g h2

lr = n2

the law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. because atoms are only rearranged in a chemical reaction, there must be the same number of sodium atoms and chlorine atoms in both the reactants and products