This video tutorial explains how to determine the oxidation numbers for elements in potassium dichromate (K2Cr2O7). It begins by identifying known oxidation numbers for potassium and oxygen, then uses these to calculate the unknown oxidation number for chromium. The tutorial emphasizes the rule that the sum of oxidation numbers in a neutral compound must equal zero. By applying this rule, the oxidation number for chromium is determined to be +6. The video concludes with a recap of the process.

What is the oxidation number of potassium in K2Cr2O7?

• +1

• +2

• 0

• -1

Which element's oxidation number is not directly known in K2Cr2O7?

• Potassium

• Chromium

• Oxygen

• Hydrogen

What is the typical oxidation number of oxygen in compounds?

• +1

• +2

• -1

• -2

Why must the sum of oxidation numbers in a neutral compound equal zero?

• To satisfy the neutrality of the compound

• To determine the charge of the compound

• To ensure the compound is stable

• To balance the equation

How many chromium atoms are present in K2Cr2O7?

• 1

• 2

• 3

• 4

What is the oxidation number of chromium in K2Cr2O7?

• +4

• +3

• +6

• +5

How is the oxidation number of chromium determined in K2Cr2O7?

• By calculating the molecular weight

• By using a spectrometer

• By measuring the compound's mass

• By using the known oxidation numbers of potassium and oxygen

What is the total oxidation number that the two chromium atoms must add up to in K2Cr2O7?

• +8

• +6

• +12

• +10

What rule is used to find the unknown oxidation number in a neutral compound?

• The rule of charge balance

• The rule of conservation of mass

• The rule of oxidation

• The rule of neutrality