To determine the moles in 40 grams of magnesium, we need the atomic weight. This can easily be found on a periodic table. For this problem, let's use 24.305 grams/mole.
We are going to set up an equation to determine this problem. In this equation, we want all our units to cancel out except for 'moles.'
In this, we can see that the unit 'grams' will cancel out to leave us with moles.
In solving the equation, we determine that there are approximately 1.65 moles of Magnesium.
Answer:
A (contains most of the mass of the atom)
Evidence has it that a proton is about 2000 times as massive as an electron.
And there is usually multiple protons and neutrons in the nucleus
From what I just said, you can say that B is wrong
C however is also wrong because protons have a +charge and neutrons are neutrle which means you always have a charge > (greater than) 0
And D is wrong because electrons (which are not in the nucleus) have a neg charge. and protons have a + charge and are in the nucleus
So your answer is A
Hope it helped
Spiky Bob
The original concentration of the acid solution is 6.175 
10^-4 mol / L.
<u>Explanation:</u>
Concentration is the ratio of solute in a solution to either solvent or total solution. It is expressed in terms of mass per unit volume
HBr + NaOH -----> NaBr + H2O
There is a 1:1 equivalence with acid and base.
Moles of NaOH = 72.90 10^-3 0.25
= 0.0182 mol.
[ HBr ] = moles of base / volume of a solution
= 0.0182 / 29.47
= 6.175 10^-4 mol / L.
Answer:
How many grams of copper (II) nitrate is formed
