Answer: The black ball will have more mass than the white ball.
Explanation: Density of a substance is defined as the ratio of mass and volume occupied by the substance.
Mathematically,

We are given that the two balls are of same size, which means that the volume of both the balls are same. We are also given that the black ball is more dense than the white ball, which means that the black ball will have more mass.
As, 
Answer:
4Ba(CO3) -> 4BaO2 + 2CO2
Explanation:
I looked at the oxygens to balance this. Ba(CO3) normally has 3 oxygens. BaO2 and CO2 have 4 oxygens total. The common multiple of 3 & 4 is 12. So there should be 12 oxygens on both sides. Then I just found the coefficients that would give 12 oxygens on both sides and can balance the rest of the atoms.
C.Pennsylvania Titusville is in the state of Pennsylvania
Entropy is also defined as a measure of the average kinetic energy of particles in a sample of matter.
1. research question
2. background research
3. hypothesis
4. <span>Controlled experiment
5. data analysis
6. data collection
7. conclusion</span>