Question

PLEASE ANSWER, I WILL GIVE BRAINLIEST AND THANKS!


48g of magnesium and 32g of oxygen react to form 80g of magnesium oxide. 2Mg + O2 --> 2MgO What mass of oxygen is needed to make 20g of MgO?

Answer 1

Answer:

8g

Explanation:

1mole of oxygen -->2moles MgO

32g --> 80g

?g --> 20g

(20x32)÷80

= 8g oxygen

Answer 2

Answer:

Mass of oxygen needed  = 8 g

Explanation:

Given data:

Mass of oxygen needed = ?

Mass of MgO formed  = 20 g

Solution:

Chemical equation:

2Mg + O₂     →    2MgO

Number of moles of MgO:

Number of moles = mass/molar mass

Number of moles = 20 g/ 40 g/mol

Number of moles = 0.5 mol

Now we will compare the moles of MgO and O₂:

                        MgO         :            O₂

                           2            :            1

                          0.5          :        1/2×0.5 = 0.25 mol

Mass of oxygen needed:

Mass = number of moles × molar mass

Mass = 0.25 mol × 32 g/mol

Mass = 8 g