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## Which of the following is an electrolyte?

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 nonmetal. However it is solid and not aqueous. Ionic compounds do not conduct electricity in their solid form, H2O water is a molecular compound and is therefore not an electrolyte (it can conduct electricity just a little bit on its own). CCl4 is another molecular comp

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

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 can eliminate choices C and D since they do not take pressure into account. We can also see that volume and temperature are directly proportional to one another. Therefore, if the temperature decreases, volume should decrease as well as long as pressure remains constant.

## Why is the boiling point of ammonia, NH3, higher then that of phosphine, PH3?

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 melting and boiling points are. Hydrogen bonding is one of the stronger intermolecular forces. These forces are present in any molecules that have NH, FH, or OH. Therefore, when looking at the two formulas, NH3 and PH3, we can notice that ammonia possesses Hydrogen bonding while p

## A characteristic common to both diffusion and active transport is that

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. Active transport, on the other hand, is the movement of molecules across a cell membrane from lower concentration into a region of higher concentration, assisted by enzymes and requiring energy. Therefore only choice (4) the movement of molecules occurs is a characteristic

## ​Which cellular change in an organism could be inherited by the next generation?

Which cellular change in an organism could be inherited by the next generation? a change in the ribosomes in the pancreas of a squirrel the deletion of a single DNA base in a sperm cell of a trout a decrease in the size of a vacuole in a rose leaf cell the transfer of a piece of a chromosome in the skin cell of a raccoon Answer and Explanation: In order for a cellular change to be inherited, this change must be present in the male gamete, or sperm or present in the female gamete, the egg or ovum. This is due to the fact that a baby is created from the fusion of an egg and sperm. Therefore, choice 2, the deletion of a single DNA base in a sperm cell of a trout, is the correct answer. If we

## What is the chemical formula of sodium sulfate?

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 charges (oxidation numbers). Sodium: Na +, sulfate SO4 2-. The formula for sulfate can be found on reference sheet in polyatomic ions section. Now, all that is left to do is to combine the ions by giving their oxidation numbers to their partners in the form of subscripts. Therefore, Na should

## Which compound is an isomer of C2H5OC2H5?

Which compound is an isomer of C2H5OC2H5? (1) CH3COOH (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 choices. Choice 1: (CH3COOH): 2 Carbon atoms, 4 Hydrogen atoms and 2 oxygen atoms, Choice 2(C2H5COOCH3): 4 Carbon atoms, 8 Hydrogen atoms and 2 oxygen atoms. Choice 3 (C3H7COCH3): 5 Carbon atoms, 10 Hydrogen atoms and 1 oxygen atom. Choice 4(C4H9OH ): 4 Carbon atoms, 10 Hydroge

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

What occurs when a catalyst is added to a chemical reaction? an alternate reaction pathway with a lower activation energy an alternate reaction pathway with a higher activation energy the same reaction pathway with a lower activation energy the same reaction pathway with a higher activation energy Answer and Explanation: Catalysts are used to speed up reactions. How do they do so? Catalysts create an alternate reaction pathway that lowers activation energy and allows reactants to be converted into products faster. Choice 1 is correct. We can think of activation energy as the mountain (energy barrier) that reactants have to overcome to become products. The higher the mountain is the harder it

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

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 electrons). Therefore let's calculate formal charges for the molecule on the left: C : 4-(4+0) = 0 N: 5-(4+0) = +1 O: 6- (1+6) = -1 Therefore, the molecule on the left has 2 charges, plus and minus one. Let's now focus on that on the right: C : 4-(3+2) = -1 N: 5-(4+0) = +1 O: 6- (2+4

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

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 give us -2 as the answer and therefore this leaves us with choice (3) as the correct answer. For amazing math tutors in NYC and online, click here #algebra