Oxidation number is charge of element in compound. Can be neutral, positive or negative.
Oxygen in dichromate has oxidation number -2, becauce there are seven oxygens, net oxidation number of oxygen is -14.
2·x(oxidation number of Cr) + 7· (-2) = -2 2x= +12
x= +6, oxidation number of one chromium is +6.
Answer: Option A. 6.022 x 10^23
Explanation:
Answer:
2 atm
Explanation:
Chemical reactions are carried out at a certain rate. Sometimes that rate is quite slow, so we want to speed things up, which is usually used by increasing temperature, increasing pressure or adding a catalyst (a substance that increases the rate without changing itself).
If this is the case, then, when writing a chemical equation, we state these special conditions over a right arrow.
Now let's look at the answers:
- 25°C is a value and unit of temperature
- ∆ is a symbol that denotes change
- 2 atm is a value and unit of pressure (atmosphere is old unit for pressure)
- Pt is a chemical symbol for platinum, an element often used as a catalyst.
So, the correct answer is C) 2 atm
