The oxidation of a neutral element is always 0.
The sum of oxidation of each element of a neutral compound always adds to 0.
For example: NaCl
Oxidation for Na is +1
Oxidation for Cl is -1
For example: MgO
Oxidation for Mg is +2
Oxidation for O is -2
Answer: c. Sugar turning black when it burns.
Explanation:
Chemical change is defined as a change in which rearrangement of atoms take place and leads to formation of new substances.
Physical change is defined as a change which leads to change in shape, size or state of the substance changes. No new substance is formed.
a) Water bubbling when it starts to boil is a physical change as it accompanies only a change in phase.
b) Detergent removing grease from a dish is a physical change as no new substance is formed.
c) Sugar turning black when it burns is a chemical change as there occurs a chemical reaction between sugar and oxygen. The oxygen in the air reacts with the sugar and the chemical bonds are broken.
d) Oil and vinegar separating in salad dressing is not a chemical change. It occurs because of difference in densities.
<h3><u>Answer;</u></h3>
= 4.81 × 10^22 particles
<h3><u>Explanation</u>;</h3>
The molar mass of Cr2(SO3)3 is 344.18 g
1 mole of a substance contains 6.02 10^23 particles
But; 1 mole of chromium (iii) sulfite = 344.18 g
Therefore;
344.18 g = 6.02×10^23 particles
27.5 g = ?
Hence;
= (27.5 × 6.02 × 10^23)/344.18
<h3><u>= 4.81 × 10^22 particles </u></h3>
The weight of the balloon is irrelevant because it is the gas that lifts it in the air. We are already given with the required volume, so we use this instead. The atomic weight of zinc is 65.38 g/mol. Assuming ideal gas behavior,
PV=nRT
P(475 mL)(1 L/1000 mL) = (1.85/65.38)(0.0821 L·atm/mol·K)(21.5 + 273)
P = 1.44 atm
Then, we use this pressure and the volume to find the moles of zinc.
(1.44 atm)(475 mL+1 mL)(1 L/1000 mL) = n(0.0821 L·atm/mol·K)(21.5 + 273)
Solving for n,
<em>n = 0.02836 moles of zinc</em>
I believe the correct answer is the geoshpere. I hope this was helpful.