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 27, 2017

If the quantity of gas remains unchanged while its temperature decreases, the volume of the gas will?

a. decrease if pressure is constant

b. increase if pressure is contant

c. always decrease

d. always increase

Answer and Explanation: The equation that gives us the relationship between Pressure, Volume, and Temperature of the gas is P1V2/T1 = P2V2/T2

Looking at this equation we can see that Pressure matters, and therefore we...

September 24, 2017

Whenever we are asked a question about boiling point, the first thing we have to take into consideration is intermolecular forces. Intermolecular forces are the forces of attraction between molecules that hold them together and are therefore directly related to the boiling points of substances. The stronger the intermolecular forces are, the harder it is to separate the molecules from one another and the higher the melt...

September 21, 2017

A characteristic common to both diffusion and active transport is that

(1) enzymes are required
(2) oxygen is moved across a membrane

(3) ATP is needed
(4) the movement of molecules occurs 

Answer and Explanation: Diffusion is the movement of molecules from the region of higher to the region of lower concentration.  Diffusion occurs passively, which means that there is no energy input in order to make the molecules move. A...

September 18, 2017

  1. Which cellular change in an organism could be inherited by the next generation?

    1.  a change in the ribosomes in the pancreas of a squirrel

    2.  the deletion of a single DNA base in a sperm cell of a trout

    3.  a decrease in the size of a vacuole in a rose leaf cell

    4. the transfer of a piece of a chromosome in the skin cell of a raccoon

Answer and Explanation: 

In order for a cel...

September 15, 2017

What is the chemical formula of sodium sulfate?

(1) Na2SO4     (2) Na2SO3

(3) NaSO4       (4) NaSO3 

Answer and Explanation: Too write a chemical formula from a name, we must first determine whether the compound is ionic or covalent. Since sodium is a metal (on the left on periodic table), sodium sulfate must be an ionic compound. Next, we will write the symbols for the two ions with their corresponding...

September 12, 2017

Which compound is an isomer of C2H5OC2H5?


(2) C2H5COOCH3

(3) C3H7COCH3

(4) C4H9OH 

Answer and Explanation:

Isomers are compounds that have exactly the same number of atoms of same elements but different structure. Therefore, we first need to count numbers of atoms in the compound C2H5OC2H5. There are 4 Carbon atoms, 10 Hydrogen atoms and 1 oxygen atom. Let's compare this to the number of atoms in the answer cho...

September 9, 2017

What occurs when a catalyst is added to a chemical reaction?

  1.   an alternate reaction pathway with a lower activation energy

  2.  an alternate reaction pathway with a higher activation energy

  3.   the same reaction pathway with a lower activation energy

  4.   the same reaction pathway with a higher activation energy 

Answer and Explanation: Catalysts are used to speed up reactions. How do they do so? Cataly...

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...

September 3, 2017

 Given f(9) = - 2, which function can be used to generate the sequence 8, 7.25, 6.5, 5.75,...?

(1) f(n)= - 8 + 0.75n
(2) f(n)= - 8 - 0.75(n -1)

(3) f(n) = - 8.75 + 0.75n

(4) f(n) = - 0.75+ 8(n- 1) 

Answer and Explanation:

First we can plug in n=9, to figure out which function would give us -2 as the answer. Choice 1, gives -1.25 as the answer for f(9)

Choice 2, gives -14.

Choice 3,  gives -2 as the answer

Choice 4, does not giv...

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