Answer:
The true statement is:
They are formed when atoms of different elements combine.
Explanation:
Compounds are formed when atoms of different elements combine.
Atoms of different elements combine with each other to attain stable electronic configuration.
The atoms can combine with each other in two different ways:
1) By sharing the electrons
2) By exchanging electrons
When they share electrons with each other, they form a covalent bond.
When they exchange electrons, they form an ionic bond.
Answer:
B.Thermal insulation minimizes energy loses to the atmosphere.
Explanation:
It is important because it helps to stop hit from transferring from the calorimeter to the environment. This would help to have an accurate measurement of the heat that was used in the chemical process. The greatest cause of error that happens in calorimetry is when heat is lost to the environment. To reduce this, you insulate the calorimeter and add a cover.
Answer:
Mass of 1 mole of copper is 63.83 g.
0.03916 moles of copper atoms have a mass equal to the 2.5 grams of copper penny.
Explanation:
Mass of 1 copper atom,m = 

Mass of 1 mole of copper :
= 
Mass of 1 mole of copper = 63.83 g
Mass of copper penny = 2.5 g
Atomic mass of copper = 63.83 g/mol
Moles of copper in 2.5 g of copper penny:

0.03916 moles of copper atoms have a mass equal to the 2.5 grams of copper penny.
Answer:
both are the types of mixture and both are impure substances that donot have fixed composition and the composition of constituents is not uniform
Answer:
Answer: 1.095 * 10^22 atoms of P.
Explanation: