Question is incomplete, the complete question is as follows:
A student wants to examine a substance by altering the bonds within its molecules. Which of the following properties of the substance should the student examine?
A. Toxicity, because it can be observed by altering the state of the substance
B. Boiling point, because it can be observed by altering the state of the substance
C. Toxicity, because it can be observed by replacing the atoms of the substance with new atoms
D. Boiling point, because it can be observed by replacing the atoms of the substance with new atoms
Answer:
B.
Explanation:
A student can examine a substance without altering the bonds within the molecules by examining its boiling point.
The boiling point is the property of a substance, at which the substance changes its state, which is from solid to liquid, liquid to gas and others. So, examining the boiling point will alter the bonds within the molecules as the state of substance will change.
Hence, the correct answer is "B".
Answer:
Law of Conservation of Energy
Explanation:
Answer is: 0,275 moles of oxygen are consumed.
Chemical reaction: 2Mg + O₂ → 2MgO.
n(Mg) = 0,550 mol.
n(O₂) = ?
from chemical reaction: n(Mg) : n(O₂) = 2 : 1.
0,550 mol : n(O₂) = 2 : 1.
2n(O₂) = 0,550 mol.
n(O₂) = 0,275 mol.
n - amount of substance.
Answer:
127529 KJ
Explanation:
Since 1gallon = 3.78 L= 3780 ml
The density of C8H18= 0.703 g/mL
Density = mass/volume
Mass= Density × volume
Mass= 0.703 g/mL × 3780 ml
Mass= 2657.34 g
Molar mass of C8H18= 114 g/mol
Number of moles= mass/molar mass
Number of moles= 2657.34/114
Number of moles= 23.31 moles
Since 1 mole evolved=5471 kJ
23.31 moles = 5471 kJ × 23.31 = 127529 KJ
