So I was taking a practice test, and there were a couple questions I had trouble with. This is my first time doing Density, so I'm a noob. Please don't just tell me the answer. If you can, show a step by step process or a formula.
A spherical ball with density 0.70 kg/L has a radius of 10 cm. If the ball is placed on the surface of water, how much of it will become submerged?
If a person's body has a density of 995 kg/m^3, what percentage of the body will be submerged gently in a) freshwater, and b) saltwater with a density of 1027 kg/m^3.
Aluminum metal reacts with HCl to produce aluminum chloride and hydrogen gas. How many grams of aluminum metal must be added to an excess of HCl to produce 33.6 liters of hydrogen gas, if the gas is at STP?
I am not a huge expert, but I'll do what I can.
For the spherical ball question, the object will sink until the amount of water displaced is equal to the object's weight, hence Archimedes principle. Since the ball is less dense than water, which is 1 kg/L, the volume of the water displaced would be less than the object's volume. You would take the ball's density 0.70 kg/L and divde it by water's density 1 kg/L and you get .7, meaning 70% of the object will be submerged.
For the second question, the same principle applies. Water has a density of 1000 kg/m^3, so 995 kg/m^3 divided by 1000 kg/m^3 and you get .995, which is 95% of the body will be submerged in freshwater. In saltwater, we use the same principles again, so 995 kg/m^3 divided by 1027 kg/m^3 and you get approxiately 0.9688, which is 96.88% submerged in saltwater.
Sorry if I dissapoint you, but I only have a vague understanding of the 3rd question. You have to understand the chemical reaction taking place using a periodic table. I'm not the best person to ask that kind of question, and I hope someone will help you and help me understand it more as well. Hope at least some of it helps.
Cheers
