For example the questions states: 'When magnesium is added to dilute hydrochloric acid, HCl, it forms hydrogen and a solution of magnesium chloride, MgCl2'
And the equation is Mg + 2HCl -> H2 + MgCl2
How to know that it is H2? And it's not only in this example, other examples are Cl2, O2, F2, how to know if they are made out of two atoms? Are there any specific group or period in the periodic table?
Thank you
And the equation is Mg + 2HCl -> H2 + MgCl2
How to know that it is H2? And it's not only in this example, other examples are Cl2, O2, F2, how to know if they are made out of two atoms? Are there any specific group or period in the periodic table?
Thank you
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There are seven elements that exist as diatomic molecules (i.e. X2) in nature because they are more stable than the lone atoms: H2, N2, O2, F, Cl2, Br2, and I2. But when they combine with other elements (e.g. HCl) they are no longer diatomic.
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If you look at the periodic table, look at the symbols. Mg is magnesium, H is hydrogen, Cl is chlorine, and they are separated atoms that are combined. HCl is hydrochloric acid, even those it is made up of hydrogen atoms and chlorine. Cl2 means two chlorine atoms or moles, same with O2 and F2.
If you are confused on how to tell, look at the letters. Mg has a lowercase g meaning is it one atom. There is no element symbolized by a lowercase g. If you look on the top left of a periodic table you will see H is buy itself. Chlorine is near the top right and Mg is mid left. Identify the symbols and learn them. This will help you distinguish.
If you are calculating, we do not use atoms, we use mols. 1 mol is 6.022 x 10^23 atoms.
In this equation, by looking hat the numbers only in front:
1 mol of MG reacts with 2 mols of HCL and produces 1 mol of H2 and 1 mol of MgCl2.
Do not worry about atoms. Find the number of mols which are given there. If it gives you atoms, you can convert to mols by dividing it by 6.022 x 10^23.
If you are taking chemistry, talk to a teacher because this is a very important concept to know.
One last thing if you are asking how they knew it would be H2, well you have to balance out everything in the equation.On the left, there is a 2 in front of the HCl meaning there must be 2 H's on the right side and 2 Cl's on the right side. So, we get H2 meaning 2 H's and Cl2 meaning 2 Cl's.
There is only one Mg on the left, so there only has to be one Mg on the right. They balance it out.
If you are confused on how to tell, look at the letters. Mg has a lowercase g meaning is it one atom. There is no element symbolized by a lowercase g. If you look on the top left of a periodic table you will see H is buy itself. Chlorine is near the top right and Mg is mid left. Identify the symbols and learn them. This will help you distinguish.
If you are calculating, we do not use atoms, we use mols. 1 mol is 6.022 x 10^23 atoms.
In this equation, by looking hat the numbers only in front:
1 mol of MG reacts with 2 mols of HCL and produces 1 mol of H2 and 1 mol of MgCl2.
Do not worry about atoms. Find the number of mols which are given there. If it gives you atoms, you can convert to mols by dividing it by 6.022 x 10^23.
If you are taking chemistry, talk to a teacher because this is a very important concept to know.
One last thing if you are asking how they knew it would be H2, well you have to balance out everything in the equation.On the left, there is a 2 in front of the HCl meaning there must be 2 H's on the right side and 2 Cl's on the right side. So, we get H2 meaning 2 H's and Cl2 meaning 2 Cl's.
There is only one Mg on the left, so there only has to be one Mg on the right. They balance it out.
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mg + Hcl ---> H2+ mgcl2 (Note you cannot change the small two at the end of an equation because it is a given ratio) eg there are two hydrogen atoms "H2"
We have one magnesium atom on both side,hence they are balanced. mg - mg
However both the hydrogen atoms and the chlorine atoms are not H - H2 and cl - cl2
the easiest way to fix this would be to change the quantity.
hence mg + 2hcl ---> h2 + mgcl2
Now we have two chlorine atoms and two hydrogen atoms to balance out the equations.
Basically by adding the larger two at the start, you are changing the quantity of hydrochloric acid.
Hope this helped.
We have one magnesium atom on both side,hence they are balanced. mg - mg
However both the hydrogen atoms and the chlorine atoms are not H - H2 and cl - cl2
the easiest way to fix this would be to change the quantity.
hence mg + 2hcl ---> h2 + mgcl2
Now we have two chlorine atoms and two hydrogen atoms to balance out the equations.
Basically by adding the larger two at the start, you are changing the quantity of hydrochloric acid.
Hope this helped.
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metal + H+ ---> M+x + H2 (unbalanced)
it is all related to activity series.
it is all related to activity series.