balance this equation. prove that it obeys the law of conservation of mass by using formula masses.
HNO3 + Mg(OH)2 ---> HOH + Mg(NO3)2
is this balanced?
2HNO3 + Mg(OH)2 ---> HOH + Mg(NO3)2
I don't understand the formula masses part do i just find the mass of each?
It isn't balanced. Do you know how to tell if it is balanced. We simply count them up on both sides.
I see 4 H atoms on the left (2 from 2HNO3 and 2 from Mg(OH)2). I see only 2 on the right. So we can stop checking there since it isn't balanced. Have another go at balancing. For the formula masses, what the problem wants you to do is to use the molar mass (formula mass) of each, multiply by any coefficients, and add everything on the left. It will be the same mass if you add everything on the right. Let me know how come out.
2HNO3 + Mg(OH)2 ---> 3HOH + Mg(NO3)2
ive done this problem before and that's what I got with the masses equaling 208 on both sides and I got it wrong
The equation isn't balanced. I see 4 H atoms on the left and I see 6 on the right. You should be able to count them up and KNOW when it is balanced.
The balanced equation is
2HNO3 + Mg(OH)2 ==> 2HOH + Mg(NO32)2
HNO3 is 63. 63 x 2 = 126.
Mg(OH)2 = 58.3
126 + 58.3 = 184.3
On the right. HOH = 18 and 18 x 2 = 36
Mg(NO3)2 = 148.3
148.3 + 36 = 184.3
That shows you how to do it. As for your answer of 208, it CAN'T be right because if it isn't balanced then the masses won't add out. However, let's check it.
Using your numbers, the left side will be the same as above; i.e.,
126 + 58.3 = 184.3
on the right, we have 18 for water. You have 3 of them so that is 3 x 18 = 54.
Mg(NO3)2 = 148.3
148.3 + 54 = 202.3
So, it not only doesn't add up, with the 3 in front, but it doesn't add up to 208. Look this over and see where you went wrong.
You really should learn how to tell when an equation is balanced. There may be an equation I can't balance BUT I know when it is right and when I need to keep working on it because i can count up the atoms on both sides. Later on you will learn that an equation must be balanced three ways.
1. the number of atoms on each side must balance.
2. the charge on both sides must balance.
3. If it is a redox equation, it must have an equal number of electrons lost and gained.
2HNO3 + Mg(OH)2 ==> 2HOH + Mg(NO32)2
I made a typo here. Obviously the Mg(NO32)2 on the right should
be Mg(NO3)2.
To balance the equation, you can follow these steps:
1. Start by balancing the atoms that appear in only one compound on both sides of the equation. In this case, we have H, N, O, and Mg.
2. Balance the hydrogen (H) atoms first. On the left side, there are 4 H atoms (2 from 2HNO3 and 2 from Mg(OH)2). On the right side, there are only 2 H atoms in HOH. To balance the H atoms, you need to multiply HOH by 2 on the right side.
2HNO3 + Mg(OH)2 ⟶ 2HOH + Mg(NO3)2
3. Balance the nitrogen (N) atoms. On the left side, there is 2 N atoms in 2HNO3. On the right side, there is only 1 N atom in Mg(NO3)2. To balance the N atoms, you need to multiply Mg(NO3)2 by 2 on the right side.
2HNO3 + Mg(OH)2 ⟶ 2HOH + 2Mg(NO3)2
4. Balance the oxygen (O) atoms. On the left side, there are 10 O atoms (6 from 2HNO3 and 4 from Mg(OH)2). On the right side, there are also 10 O atoms (4 from 2HOH and 6 from 2Mg(NO3)2). The equation is now balanced.
2HNO3 + Mg(OH)2 ⟶ 2HOH + 2Mg(NO3)2
Now, let's check if the equation obeys the law of conservation of mass by using the formula masses:
The molar mass (or formula mass) of HNO3 is calculated as follows:
(1 H x 1.01 g/mol) + (1 N x 14.01 g/mol) + (3 O x 16.00 g/mol) = 63.02 g/mol
The molar mass of Mg(OH)2 is calculated as follows:
(1 Mg x 24.31 g/mol) + (2 O x 16.00 g/mol) + (2 H x 1.01 g/mol) = 58.33 g/mol
On the left side, we have 2HNO3, so the total mass is:
2 x 63.02 = 126.04 g
On the right side, we have 2HOH (water), so the total mass is:
2 x 18.02 = 36.04 g
We also have 2Mg(NO3)2, so the total mass is:
2 x [ (1 Mg x 24.31 g/mol) + (2 N x 14.01 g/mol) + (6 O x 16.00 g/mol) ] = 296.62 g
As we can see, the total mass on the left side (126.04 g) is equal to the total mass on the right side (36.04 g + 296.62 g = 332.66 g). Therefore, the equation obeys the law of conservation of mass.