Given the equation 4al +3o2 --> 2al2o3 if 325 grams of al2o3 are to be formed, determine the mass of aluminum that must be reacted with excess oxygen. question 4 options: 101.77g al 26.9g al 171.80g al 6.38g al

172 g Al

Step-by-step explanation:

We know we will need a balanced equation with masses and molar masses, so let’s gather all the information in one place.  

M_r:   26.98                101.96

            4Al + 3O₂ ⟶ 2Al₂O₃

m/g:                               325

(a) Calculate the moles of Al₂O₃

n = 325 g Al₂O₃ × 1 mol Al₂O₃ /39.10 g Al₂O₃

n = 3.188 mol Al₂O₃

(b) Calculate the moles of Al

The molar ratio is (4 mol Al/2 mol Al₂O₃)

n = 3.188 mol Al₂O₃ × (4 mol Al/2 mol Al₂O₃)

n = 6.375 mol Al

(c) Calculate the mass of Al

m = 6.375 mol Al × (26.98 g Al/1 mol Al)

m = 172 g Al

Note: The answer can have only three significant figures because that is all you gave for the mass of Al₂O₃.

african americans demonstrated their newly found freedom by relocating often in search of relatives whom they had been separated from during slavery. others established schools to educate freed people and they built institutions such as churches and political organizations to advocate for their rights.

what is the average time it took the car to travel 0.25 meters?

⇒ 2.23 seconds

what is the average time it took the car to travel 0.50 meters?

⇒ 3.13 seconds