(2) U-238 is the radioisotope used in dating geological formations. Uranium-238 has a half-life of 4.46 billion years, which makes it suitable to date such old formations.
The other options do not have such long durabilities and half-lives.
Answer: C
Explanation:
A. Shows 3-Hexyne (NOT 2-HEXYNE)
B. Shows 7 carbons (too many) (NOT 2-HEXYNE)
C. Shows a triple bond (yne) and 6 carbons and it's on the second carbon (2-HEXYNE)
D. Shows two substitent on the second carbon but the triple bond is on the 3rd carbon so it's 2,2-dimethyl-3-heptyne (NOT 2-HEXYNE)
A) K is the element with the lowest electronegativity
To convert a mass of a substance to units of moles, we would need the molar mass of the substance since is it describes the mass of one mole of that substance. For CuCl2, the molar mass is 134.45 g/mol. For Al, the atomic mass is 26.98 g/mol.
2.50 g CuCl2 ( 1 mol / 134.45) = 0.019 mol CuCl2
0.25 g Al ( 1 mol / 26.98 g ) = 0.0093 mol Al
