Answer:
Burning is a chemical process by which two atoms or molecules will combine with each other. In burning, the two atoms or molecules will combine and release energy.When the molecules combine and release energy, it is released in the form of heat and often light.Different compounds react with oxygen differently – some contain lots of heat energy while others produce a smaller amount.The bigger the fuel load, the more intense the fire will be in terms of heat energy output. Moisture content: If the fuel isn't dry enough, it won't burn.Flames consist primarily of carbon dioxide, water vapor, oxygen and nitrogen. If hot enough, the gases may become ionized to produce plasma. Depending on the substances alight, and any impurities outside, the color of the flame and the fire's intensity will be different.
Answer : The final temperature of the mixture is 
Explanation :
In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.


where,
= specific heat of iron = 
= specific heat of water = 
= mass of iron = 39.9 g
= mass of water = 
= final temperature of mixture = ?
= initial temperature of iron = 
= initial temperature of water = 
Now put all the given values in the above formula, we get


Therefore, the final temperature of the mixture is 
20.
Atomic number is equivalent to its protons and electrons. :)
Answer:
1. 505g is the mass of the aluminium.
2. The answer is in the explanation
Explanation:
1. To solve this question we need to find the volume of the rectangle. With the volume and density we can find the mass of the solid:
Volume = 7.45cm*4.78cm*5.25cm
Volume = 187cm³
Mass:
187cm³ * (2.702g/cm³) = 505g is the mass of the aluminium
2. When the temperature of a liquid increases, the volume increases doing the density decreases because density is inversely proportional to volume. And works in the same way for gases because the temperature produce more collisions and the increasing in volume.
Copper (II) Carbonate + Heat yields copper (II) oxide and carbon dioxide
Molecular Equation: CuCo3 + heat > CuO + CO2