I'm homeschooled, and my chemistry book isn't explaining this right -- please help!?

Question

Hi, I'm having a bit of trouble with conversion factors in chemistry. The book is explaining it in an extremely complicated way, and I'd do it in my own way much quicker, but you have to show the work using their steps, etc., so I need to figure out what exactly it's talking about. Here's an example of the problem:

A car can travel 40.0 miles on one gallon of gasoline. How many kilometers per liter is this? (1.61 km = 1 mi; 1L = 1.06 quarts; 1 gallon = 4 quarts)

I *think* that they want it to be set up something like this:

40 mi /1 gallon X 1.61 km/ 1 mi X 1.06 quarts/ 1 L X 1 gallon/ 4 quarts


... which, if solved by the methods they present in the book, would come out to 64.4 km / .265 L. When this is put into the format of X km/L, would it be 243 km/ L? Please explain this to me! THANK YOU

I guess it could also be set up as:

40 mi/ 1 gallon X 1.61 km/ 1 mi X 4 quarts/ 1 gallon X 1 L / 1.06 quarts

... thus making the answer 64.4 km/ 3.77 L. Or rather 17.08 km / L.

Answer 1

Conversions are based on equalities.

40 miles = 1 gallon
1.61 km = 1 mile
1.06 Qts = 1 L
4 Qts = 1 gallon

Now, just set up your equalities so that your multiplication cancels your unwanted units leaving you with your desired units of measure.

40 m/g x 1.61 km/m x 1 g/4qts x 1.06 qts/L = 17.066 km/L

Answer 2

The setup that you wrote is correct and you check it by canceling out the units. The only ones remaining are km over liters which is what you want so it is right. As for number, go ahead and do the multiplication and the division and then number that you got 64.4 KM/0.265L is wrong. It should be be 68.264km/4 liters which gives you 17.066km/L.

Answer 3

Sometimes getting the answer isn't always the point. Examples are used to show concepts in action. Oftentimes there can be a better way of doing something, but try not overlook the concept they are trying to teach. In high school I had a struggle with this in chemistry for the same reason. But I realized later that it was more about learning the systematic way than just getting the answer. If you go into engineering later or chemistry you may find it helpful to follow this method they are trying to teach. This "extremely complicated way" is what is actually being taught, not simply getting the answer.

God bless you.

Answer 4

You have the right idea, and I know that it is a lot easier to do it your own way, it's like that for me too! Science books think they know how to do math, and I'm like no... lol but anyways..

You have to set up the multiplication so that the labels cancel out, basically. You did that part right. So multiply whatever is left over after you cancel all your labels and simplify. I got 17.066 km/L, i don't know what you did, maybe you multiplied wrong?

I hope I helped.

Answer 5

the reason that the product formed is BeO will be derived from the periodic table. factors in crew IIA (The Alkaline Earth Metals) have a tendency to style 2+ ions because dropping 2 electrons supplies them a valence shell with an octet (noble gas configuration). Beryllium is in crew IIA, so as it is what it is going to do. In an ionic bond, oxygen atoms have a tendency to attain 2 electrons by means of the undeniable fact that can supply them an octet besides. each and every beryllium atom has 2 electrons it may lose in an ionic bond, so each and every beryllium can in effortless words react with a unmarried oxygen atom. in spite of the undeniable fact that, oxygen gas is diatomic, so there are actual 2 oxygen atoms obtainable. It therefore takes 2 beryllium atoms to react with one oxygen molecule (O2), so as which skill beryllium would have a coefficient of two. Then, to maintain an equivalent style of atoms on both fringe of the equation, a subscript of two could be extra to beryllium oxide.

Answer 6

The formula is right, but your math is wrong. somehow you inverted the 4. You should get 68.264 / 4 = 17.066 km/L