Given: 4al + 3o2 → 2al2o3 in this chemical reaction, how many grams of al2o3 will be produced if 375 grams of al react completely? express your answer to three significant figures. there will be grams of al2o3.

≈ 708

Explanation

Here we have equation as:

                        4 Al     +    3 O₂    →    2 Al₂O₃

As we know:  

                       No of moles = Mass/ Molar mass

Here, Mass is 375 g and Molar mass is 27 gms, so no. of moles of Al will be:

                                            =375 g /27 g/mol

                                               =  13.889 mol

About mole ratio, we can see that for 4 moles of Al , 2 moles of Al2O3 are formed, so for 13.889 moles of Al, 13.889 mol ÷ 2 =6.944 moles of Al₂O₃ will be formed.

As we know:  

                            Mass= No of moles/Molar mass  

                      Mass of Al₂O₃ = 6.944 mol × 102  g/mol

                                           = 708.288 g

Hope it helps!

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)