Given that 1 mole contains 6.02x10^23 molecules, 3.0x10^23 is just around half a mole. Then we check the number of moles for each choice:
A. This is approximately half a mole, since the molar mass of Br2 is 159.8 g/mol.
B. He has a molar mass around 4 g/mol, so this is 1 mole.
C. H2 has a molar mass of 2.02 g/mol, so this is 2 moles.
D. Li has a molar mass of around 6.97 g/mol, so this is around 2 moles.
Therefore the only choice that fits is A. 80 g of Br2.
Answer: C
Explanation:
In endothermic reactions, enthalpy is positive, and in exothermic reactions, enthalpy is negative, So, if enthalpy is positive, then it is an endothermic reaction, and hence is required for the reaction to occur.
Answer:
A. More mass
C. Shorter distance between them
Explanation:
The two characteristics of a body experiencing greater gravitational force are that they have mass and a shorter distance between them.
This is conformity with Newton's law of universal gravitation.
The law states that "every object attracts one another with a force that is directly proportional to their masses and inversely proportional to the square of the distance between them".
This law implies that the more the mass of two bodies, the more the gravitational force of attraction. And that the shorter the square of the distance between them, the more the attraction.
Answer: C... Because Zinc is made of only one type of atoms.
Explanation: All elements are made of one type of atom. Pure gold is made out of only gold atoms, silver out of only silver atoms, etc.