November 21, 2017

Exothermic reactions are reactions that release energy. An example of exothermic reactions is combustion or burning. Endothermic reactions on the other hand absorb energy. An example of an endothermic reaction is melting of ice.

For exothermic reactions, since the heat is released, we see heat on the product side of the equation. Also, change in enthalpy will have a negative sign.

For endothermic reactions, since the heat...

October 30, 2017

CH3CH2COOH(aq) + H2O(l) --->  CH3CH2COO−(aq) + H3O+(aq) 

The key to idenitifying Bronsted-Lowry acid-base pair and realizing that acid and base must differ in only one Hydrogen. According to the theory, Bronsted-Lowry acid is a proton (H+) donor, and Bronsted-Lowry base is a proton (H+) acceptor. When looking at the equation we must first look at reactants and then at products. In the equation given above, we see th...

October 3, 2017

A molecule must be nonpolar if the molecule

(1) is linear
(2) is neutral
(3) has ionic and covalent bonding
(4) has a symmetrical charge distribution 

Answer and Explanation:

 A molecule is considered to be non polar when the charge is symmetrically distributed in it or when there is an equal sharing of electrons between the two atoms of a diatomic molecule . Examples of non polar molecules are : O2, CH4, CCl4. In these mo...

September 30, 2017

Which of the following is an electrolyte?

a. NaCl (s)

b. H2O

c. CCl4

d. NaCl (aq)

An electrolyte is a substance that is capable of conducting electricity. To identify an electrolyte when gives formulas we must first make a list. 

List of electrolytes: Ionic compounds (aqueous), Metals, Strong Acids and Strong Bases.

Let's now take a look at the answer choices.

NaCl (s) is an ionic compound since it is composed of a metal and a...

September 6, 2017

Two possible Lewis electron-dot diagrams for fulminic acid, HCNO, are shown below.

Explain why the diagram on the left is the better representation for the bonding in fulminic acid. Justify your choice based on formal charges. 

The most stable resonance form of a molecule has the least formal charges.

To calculate formal charges we can use the following formula.

#of valence e's - (number of bonds + number of lone electron...

August 30, 2017

Which molecular formula is also an empirical formula?

(1) C6H6

(2) H2O2

(3) N2H4

(4) N2O5 

Answer and Explanation:

An empirical formula is a formula where the subscripts of the elements are in their lowest whole number ratio. In other words, we can not divide them anymore.

Let's take a look at each answer choice. Choice 1 is C6H6, we can divide both numbers by 6 and therefore this formula is not empirical. Moving to choice 2,...

August 27, 2017

Compared to a potassium atom, a potassium ion has

(1) a smaller radius

(2) a larger radius

(3) fewer protons

(4) more protons 

Answer and Explanation: Let's first look at the periodic table on the reference sheet to find out what kind of ion does potassium have? If we look at the top right of K (potassium), we see the charge plus 1. Therefore, the ion of potassium has a +1 charge. +1 charge means that potassium atom has lo...

August 24, 2017

In order to determine the overall reaction order, we need to look at the rate law. Rate law has a general formula Rate = k[A]^m [B]^n where A and B are reactants. Rate law can also look like this Rate = k[A]^m if there is only one reactant in the equation or it can have more reactants depending on the equation given.

In order to determine the overall reaction order all we need to do is simply add the exponents of the rea...

July 13, 2017

(1) +1

(2) +2

(3) +29

(4) +64 

Answer and explanation:

What particles are inside the nucleus of an atom? Protons and neutrons. Protons have a charge of plus one while neutrons have no charge (neutral). Therefore, the charge of nucleus of copper atom must be equal to the charge of the protons inside the nucleus. How many protons does Copper have? The number of protons is equal to atomic number which we can find by looking...

March 2, 2017

Strong acids dissociate completely. What does it mean? If a strong acid is put into water, it will break completely into H+ and whatever it left (for example HCl --> H+ and  Cl-). So if I start with 3 moles of HCl , it will break and give 3 moles of H+ and 3 moles of Cl-.

A weak acid, on the other hand, dissociates only partially. For example, if I start out with 3 moles of acetic acid, only 0.002 moles of it will b...

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