12.) This does not follow the rule of conservation because on the reactant side there is one Na and two Cl while the product side only has one Na and Cl. They are not equal and do not have the same number of atoms for the different elements. In the law of conservation matter cannot be created or destroyed and this does not follow the law.
13.) 2Na + Cl2 —> 2NaCl
Put a 2 in front of Na and a 2 in front of NaCl
Take the LCM of the three numbers. Since 2 is a multiple of 4, you can ignore the two and just take the LCM of 4 and 3.5. Since 3.5 is a decimal, the LCM is just 3.5*4 which is 14. That is how many minutes after 8:00 they will flash together again.<span />
Answer:
3
Step-by-step explanation:
440 gallons of 80 % antifreeze solution must be mixed with 80 gallons of 15% antifreeze to get a mixture that is 70% antifreeze
<em><u>Solution:</u></em>
Let "x" be the gallons of 80 % antifreeze added
Therefore, "x" gallons of 80 % antifreeze solution must be mixed with 80 gallons of 15% antifreeze
Final mixture is x + 80
Therefore, we can frame a equation as:
"x" gallons of 80 % antifreeze solution must be mixed with 80 gallons of 15% antifreeze to get (x + 80) gallons of 70 % antifreeze
Thus, we get,
x gallons of 80 % + 80 gallons of 15 % = (x + 80) gallons of 70 %

Thus 440 gallons of 80 % antifreeze solution must be mixed
80,000 per year....there are 12 months in a year
80,000 / 12 = 6666.67 per month