## How To....

chrisavalos-2L
Posts: 63
Joined: Fri Sep 28, 2018 12:18 am

### How To....

I was wondering when balancing a chemical equation if you need to put the state of matter? Also I was wondering what the best technique is to begin balancing any equation?

Jessica Dharmawan 1G
Posts: 32
Joined: Fri Sep 28, 2018 12:15 am

### Re: How To....

I believe Dr. Lavelle said we should include the state of matter when balancing an equation. We will probably be able to recognize the states of matter as we go along and do problems, so I think we will pick it up eventually. If not, then the state of matter will be stated in the question.

To balance a chemical equation, I start off with writing down the number of atoms of each element present from the reactants and from the products. Then I look at the element with the least amount of constituent atoms on either the reactant/product side and start balancing from there.

Saima Salam 3J
Posts: 32
Joined: Fri Sep 28, 2018 12:25 am

### Re: How To....

When balancing an equation, the state of matter might be provided by the equation but if not then there are some common ones that we should know. For example, if we have H2, O2 or N2 then we know that they are gaseous elements. However, in the case of I2, the state is solid in room temperature and Br2 is liquid. So my point is that there are some basic ones that Dr. Lavelle wants us to know but other than that it should be provided.

In balancing a chemical reaction, I usually write down the number of atoms of each element given on either side of the reaction. Then, I compare how many I need if each and multiply by the appropriate multiple. One tip that I use that I try to balance elements that are listed only once on each side of the reaction and not multiple times. For example, C6H14 + O2 → CO2 + H2O; in this case balance the Oxygen last because they occur two times in the product.

Posts: 81
Joined: Fri Sep 28, 2018 12:28 am

### Re: How To....

Knowing the state of a particular element or compound may be essential in balancing chemical equations, however it may be very difficult to know many of them by heart. In my opinion, knowing the state of the matters are helpful in visualizing a particular reaction but even if not given, the problem is still possible to complete.

When balancing equations, I usually get an estimate just by looking at the equation as to which side would need to be worked on the most. This can be seen by writing down the number of atoms on both sides of the given equation, from there it can be seen what needs to be done in order to ensure a proper balance.

Maria Nabagala 3E
Posts: 30
Joined: Fri Sep 28, 2018 12:24 am
Been upvoted: 2 times

### Re: How To....

When balancing equations, I usually just list how much of each element is present (a technique I learned in High school), from there I just balance the equation from left to right taking into consideration the number of elements on each side.

Aaron Ang 4H
Posts: 30
Joined: Fri Sep 28, 2018 12:28 am

### Re: How To....

The question about adding the state of matter to a chemical equation was brought up in my discussion today and the TA said that the questions asked on the tests should be pretty self explanatory in this regard and that we would definitely be able to infer the state of matter.

As for balancing a chemical equation, I normally start off by identifying all the different elements and the number of atoms of each element that are present in the equation. Then, I proceed to balance each element one by one on both side of the equation until the number of atoms of each element matches up on each side of the equation

sonalivij
Posts: 70
Joined: Fri Sep 28, 2018 12:27 am

### Re: How To....

Typically, when I balance chemical equations I count how many of each element is on the reactants side and the product side and then start off by balancing the element that is in the least amount of compounds. After that I balance the next compound that has the least amount of an element and so on until each element is equal on both sides.

Matthew Mar 1J
Posts: 61
Joined: Fri Sep 28, 2018 12:15 am
Been upvoted: 1 time

### Re: How To....

For the question on labeling states of matter, I'm pretty sure they will usually be given unless it's something like a combustion reaction where we should know that the products will be CO2 and H2O in gas form.

Brianna Brockman 1F
Posts: 60
Joined: Fri Sep 28, 2018 12:23 am

### Re: How To....

You don't have to put the state of matter unless it asks you to, the way I understand it.

Meghanhe1l
Posts: 60
Joined: Fri Sep 28, 2018 12:17 am

### Re: How To....

Today during our test, our TA told us that states are not required for our reactons

Rachel Dang 1H
Posts: 32
Joined: Fri Sep 28, 2018 12:17 am

### Re: How To....

States of matter will come into play later when we go into topics like entropy and intramolecular forces but for now we don't really need to worry about them when writing chemical equations.

KHuang1L
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

### Re: How To....

I like to begin by writing down all the elements and how many atoms there are in each side first, starting with elements in fewer molecules. Looking at those numbers, I add stoichiometric coefficients to balance the two sides.

Isabelle_Maletz_3E
Posts: 27
Joined: Fri Apr 06, 2018 11:03 am

### Re: How To....

Putting the states of matter in a chemical reaction really only becomes important when dealing with reactions that cause a change in state for one or more chemicals. However, for this class I don't believe it's required unless stated in the question.

Tyler Vu 4I
Posts: 30
Joined: Fri Sep 28, 2018 12:27 am

### Re: How To....

It is hard to memorize the states of matter for every equation but there are a lot of easy ones to remember. Understanding the states of the reactants can let us know if there is a precipitate out of solution.

StudentD2B
Posts: 43
Joined: Fri Sep 28, 2018 12:27 am

### Entropy and Enthalpy

How much are we going to have to know about entropy and enthalpy and Gibbs Free Energy for the final. It is mentioned quite a few times in the sections in the book (7th edition Focus 6B.1 and 6C.3 - 6C.4) There are also a bunch of equations we didn't cover in class, do we need to know how to use those?

StudentD2B
Posts: 43
Joined: Fri Sep 28, 2018 12:27 am

### Re: How To....

Also are we responsible for table 6C.4 "Contributions to the Enthalpy of Proton Transfer of Binary Acids*"

StudentD2B
Posts: 43
Joined: Fri Sep 28, 2018 12:27 am

### Book interpretations

In the 7th edition Focus 6C.3-4, when they reference HA, H-A, and A, what does the "A" stand for. Is it any acid or any acidic oxide or what?