Answer: The given quantity is 2 moles of magnesium or 48 g of magnesium.
The unknown quantity is mass of MgO in grams.
Molar mass of MgO = 40 g
Explanation: 
As can be seen from the chemical equation, 2 moles of magnesium react with 1 mole of oxygen gas to give 2 moles of MgO.
According to mole concept, 1 mole of every substance weighs equal to its molar mass.
Thus 
of magnesium produce=
of MgO.
Molar mass is the mass in grams of 1 mole of the substance.
Thus if 2 moles of MgO weigh= 80 g
1 mole of MgO will weigh=
Thus molar mass of MgO is 40 g.
26, protons and nuetrons will always be the same
Explanation:
The cyclic universe theory is a model of cosmic evolution according to which the universe undergoes endless waves of expansion and cooling. It's any of several cosmotoligal models in which the universe follows infinate, indenfinate, self-sustaining practices.
I hope my answer helped you! Have a great day!
A rating and a Thanks would also be great!
<span>The answer is D) 108 million kilometers. To solve this problem, you must perform a simple unit conversion calculation. 1 AU = 150,000,000 km is the conversion factor. Take the radius of Venus, .72 AU, and multiply it by 150,000,000 km/1 AU. You flip the conversion factor so that the units of the original distance in the numerator cancel the units in the denominator of the conversion factor. completing the calculation gives you 108,000,000 km</span>
The answer to this question is 2 and 3
