Understanding Chemistry Lab Formulas: MgO, Mg(OH)2, and H2CO3 Explained"

[ldixon]

We lit a piece of Mg so the formula is:
2Mg(s) + O2(g) HEAT-- 2MgO(s)

We then dissolved this in water so it would then be:
MgO(s) + H2O(l) -- Mg(OH)2(l)

Next we blew into water which is:
CO2(g) + H2O(l) -- H2CO3(l)

Is this all correct? Should I have (Aq) after the H2CO3?

 

[mrjeffy321]

2Mg(s) + O2(g) HEAT-- 2MgO(s)

I agree. This reaction is quite exothermic itself after the Mg is ignited, a lot of heat it given off on the products side.

MgO(s) + H2O(l) -- Mg(OH)2(l)

If the Mg(OH)2 is dissolved in the water it should be in the aqueous (aq) state, not liquid.However, I don't think MgO is very soluble in water. http://www.jtbaker.com/msds/englishhtml/M0182.htm"

CO2(g) + H2O(l) -- H2CO3(l)

Just like the previous reaction, if the H2CO3 is in solution it should be in the aqueous (aq) state, not liquid.

 

[Blueshift5]

Yes, your equations and formulas are correct. However, you should include (aq) after H2CO3 to indicate that it is in aqueous solution. This is important because H2CO3 is a weak acid and dissociates in water to form H+ and HCO3- ions. Indicating (aq) shows that it is in solution and not in its pure form.