Group 1A and 2A Reactions - Video Tutorials & Practice Problems
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1
concept
Reaction with H2O
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1m
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Here we're going to say that alkaline metals, the elements in group 1A, and alkaline earth metals from group 2A, undergo numerous reactions. Now the 2 types of reactions that we're going to pay attention to are those that have them reacting with either water or a halogen from group 7a. Now here we take a look at the reaction with water, we're going to say both groups react violently with water, and have high exothermic, so delta H of hydrations. Now recall when metals react with an acidic proton, H2 gas is formed. Here we have an example of a reaction of these metals with water, and in particular we're looking at group 1A. Now with group 1A, we're going to say that our metal from group 1A reacts with water, it's going to generate H2 gas. In addition to this, it would produce our metal ion, and since it's in group 1 a, it's plus 1. If it were in group 2 a, it'd be plus 2, plus hydroxide ion. And we said that this is a highly exothermic reaction, remember exothermic means we're releasing heat, so heat would be a product. Once we balance this out, we'd have to put a 2 here, here, here, and here, and this will represent my balanced equation between the reaction of group 1 a metal with water. Now remember, m here could stand in for a group 1 a or a group 2 a metal.
2
example
Group 1A and 2A Reactions Example
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44s
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Here it says we need to complete and balance the following reaction. So from group 1 a, we have potassium solid reacting with liquid water. Now, from our example that we saw earlier, we know that this will produce h two gas. We know that it would produce 2 moles of Potassium ion, aqueous. It will produce 2 hydroxide ions, aqueous, plus the generation of heat. It is an exothermic process, so heat would be a product. Now in addition to this, we'd have a 2 here and a 2 here to finish balancing out our reaction. So this would represent our complete and balanced reaction between the reaction between the reacting of potassium solid and liquid water.
3
Problem
Problem
Alkaline earth metals react with certain substances to produce hydrogen gas. Which of the following will result in hydrogen gas formation? Provide a balanced reaction.
a) Beryllium (Be) and O2
b) Barium (Ba) and CO2
c) Calcium (Ca) and H2O
d) Strontium (Sr) and O2
A
Beryllium (Be) and O2 2 Be(s) + O2(g) → 2 BeO(s)
B
Barium (Ba) and CO2 Ba(s) + 2 CO2(g) → BaO(s) + CO(g) + heat
Now when it comes to the reaction with halogens, we're gonna say both groups 1a and 2a react with halogens to produce ionic halides. If we take a look here, if m here represents a group 1a metal, it reacts with a diatomic halogen to produce an ionic halide. Remember, group 1 a is plus 1 in charge, halogens are in group 7 a, so they're minus 1. The numbers are the same, so they just cancel out. So our ionic halide is m x. We have to balance this out, there's 2 halogens here but only 1 here, so I throw a 2 here. But now I have 2 metals on the product side, so I would have to put a 2 here. M could also represent a group 2 way metal, which have a charge of 2 plus or plus 2. They would still react with the halogen, which is minus 1, and create m x 2 solid as a product. In that case, you get that as a product and you'd still have to balance out your overall reaction if necessary. So just remember, group 1a and 2a metals react with diatomic halogens to produce ionic halides.
5
example
Group 1A and 2A Reactions Example
Video duration:
40s
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Here it says to complete and balance the following reaction. Here we have lithium's cells reacted with diatomic fluorine gas. So we know here that lithium's in group 1 a, so it's plus 1. Fluorine's in group 7 a, so it's minus 1. As a result, we create lithium fluoride. We still have to balance this reaction, so I'd put a 2 here so both sides have 2 fluorines, and I'd have to put a 2 here so that both sides have 2 lithiums. This would represent our complete and balanced reaction between lithium fluoride, well, between lithium solid and Fluorine gas in the production of lithium fluoride.
6
Problem
Problem
Provide the products from the reaction between strontium and aqueous chlorine.