Now I'm just going to assume you mean Charles law. So when working with gases, there are 4 properties: pressure, volume, temp, and quantity. The simple gas laws deal with 2, while leaving the other 2 constant. If Charles' Law changes temp and volume, what 2 stay constant? Pressure and quantity
The correct answer is - B) 650.
The Red Sea is a sea that grows in size because it is widening all the time. The rate of the widening is 1.25 centimeters per year, so it is not something that can be easily seen during a normal human lifespan, but over a longer period of time it will have a much different shape, size, and influence in the region. It is located between the African and the Arabian tectonic plates as an elongated thin sea with a northwest-southeast direction.
The widening of the Red Sea is due to the movement of the tectonic plates. Africa is moving towards northwest, and that makes it slowly distance itself from the Arabian plate, thus opening more space for the Red Sea.
In order for the Red Sea to widen another 812.5 centimeters, will be required 650 years, and we can come to the result by simple dividing the required number of the width with the annual widening.
812.5 / 1.25 = 650.
Mixing calcium carbonate and HCl.
Heating copper sulfate pentahydrate.
Mixing potassium iodide and lead nitrate.
Combining magnesium and hcl.
Burning the candle.
Let's look at the available options and see what are chemical changes and what are physical changes. As a side note, line breaks, capitalization, and punctuation are VERY important. I spent almost as much time attempting to actually figure out what your options were as I spent in distinguishing between what were chemical reactions and physical changes.
Crushing calcium carbonate.
* This is a mere physical change. You start with large pieces of calcium carbonate and end up with smaller pieces. So this is a bad choice.
Mixing calcium carbonate and HCl.
* This is a chemical reaction where the calcium carbonate and hydrochloric acid react with each other and produce carbon dioxide plus other compounds. So this is a good choice.
Boiling water.
* Another physical change from liquid to vapor. You can cool down the resulting vapor and end up with the original water. So this is a bad choice.
Heating copper sulfate pentahydrate.
* This is a chemical change in that you're converting CuSO4 . 5H2O(s) into CuSO4 and H2O. So this too is a good choice.
Separating iron filing and sulfur.
* You start out with iron filings and sulfur and end up with iron filings and sulfur. Things are a bit more orderly, but no chemical reactions have occurred. So this is a bad choice.
Mixing potassium iodide and lead nitrate. * You start with 2 white solids and upon mixing them, you get a yellow solid.
A chemical reaction has occurred. So this is a good choice.
Combining magnesium and hcl.
* When you combine these two items, you get hydrogen gas as a product. So you have a chemical reaction. And this is a good choice.
Burning the candle.
* Another chemical reaction. The wax combines with the oxygen in the air and produces water vapor and carbon dioxide. So this is a good choice.