# algebra

posted by .

write a direct variation equation that
relates atoms of O oxygen to atoms of hydogen H Mary combined 8 atoms of hydrogen and 4 atoms of oxygen to get 4 molecules of water

is this equation correct?
O + 2H = WM

• algebra -

In chemistry class you might write an equation in that fashion to suggest that 1 molecule of water is composed of the "sum" of 1 oxygen atoms and 2 hydrogen atoms.

In your math work, since you are doing the topic of "direct variation" you are expected to think about how the quantities vary. That means an equation of the form y = kx, where k is a constant and x and y are the variables.

In this case, what is asked for is the ratio of hydrogen to oxygen, which is constant no matter how many molecules you are talking about.

For example, you could have (oxygen, hydrogen) values of (1, 2), (2, 4), (3, 6), (4, 8), etc.

This can be expressed as H = 2O, in other words, number of hydrogen atoms is two times whatever the number of oxygen atoms.

y = k * x
H = 2 * O

In this case, the equation is expressing how hydrogen "varies directly" with oxygen. The constant of variation is 2.

You could also write this:

y = k * x
O = (1/2) * H

That would express how oxygen varies directly with hydrogen. The constant of variation is 1/2.

Graph of y = kx is a line through (0, 0) always. The slope of the line is k.

So instead of an "addition" equation, direct variation is always a "multiplication" equation.

Note: If you have a situation that does not pass through (0, 0), it is not considered "direct variation."

So, y = 3x + 5 is not direct variation.

• algebra -

Thank you very much for explaining it to me. I am taking my first algebra course and I am having a difficult time in undestanding my text. You made this so clear. I really appreciate it. thanks Ann

• algebra -

COrrect ! great job

## Similar Questions

1. ### Chemistry

A compound containing 3 atoms of carbon and 8 atoms of hydrogen is combined in a reaction with oxygen molecules. The two end products of this equation are carbon dioxide and water. What element should you look at first in balancing …
2. ### Intro. Chemistry

Based on the law of definite composition, Dalton proposed that one atom of carbon combines with two atoms of oxygen to always produce CO2. Similarly,he proposed that two atoms of hydrogen combine with one atom of oxygen to give a molecule …
3. ### math

the ratio of hydrogen atom to oxygen atoms in water is 2:1 if an amount of water contains 341 trillion atoms of oxygen how many hydrogen atoms are there?
4. ### Science

How many atoms of aluminum can be produced by the decomposition of 47.1 g of Al2O3?
5. ### biology

Choose the total number of each item requested below. 4C6H12O6 Carbon atoms Hydrogen atoms Oxygen atoms Molecules
6. ### math

What is one mole of H2O composed of? A. 2 hydrogen atoms and 1 oxygen atom B. 2 × (6.02 × 1023) hydrogen atoms and 6.02 ×1023 oxygen atoms C. 3 atoms of water and 2 oxygen molecules D. one half of a molecule of peroxide I say A
7. ### Algebra

Joyce combines 9 atoms of hydrogen and 3 atoms of nitrogen to make 3 molecules of ammonia. write a direct variation equation which relates atoms of hydrogen to atoms of nitrogen. How many nitrogen atoms does Joyce need to form ammonia …
8. ### Science URGENT

Write down the number of hydrogen and oxygen atoms of the following H2O 3H2O 5H2O Write down the number of carbon, hydrogen and oxygen atoms: C6H12O6 2C6H12O6 10C6H12O6 Write down the number of molybdenum, oxygen and hydrogen atoms: …
9. ### Math

Glucose is a common type of sugar. One glucose molecule is made up of 24 atoms. 1/4 of the atoms are carbon, 1/2 are hydrogen atoms, and 1/4 are oxygen atoms. Part A: How many oxygen atoms are there in 50 atoms?
10. ### chemistry

how many molecules are in 5.5 moles of oxygen gas?

More Similar Questions