Answer:
4.09×10⁻³ is the mole fraction of sucrose
Explanation:
Mole fraction = Moles of solute or solvent/ Total moles
Let's convert the mass to moles (mass / molar mass)
38.6 g / 342 g/m = 0.113 moles of sucrose
495 g / 18 g/m = 27.5 moles of water
Total moles = 0.113 m + 27.5 m = 27.0613 moles
Mole fraction of sucrose = Moles of sucrose / Total moles
0.113 m / 27.0613 moles = 4.09×10⁻³
So you have to multiply 786,3 times 0.98 to get the mass the mass is 770.57 if u round its 770.6 or 771
The answer is 7. Valence electrons are the electrons in the very last shell, so we need to look at the outer “circle” and count the electrons, or the little black dots. There are 7 in the last shell.
D) burning magnesium ribbon, as combustion is a chemical reaction so causes chemical change. The other 3 options do not involve reactions so there isn't a chemical change.
