Answer : The balanced chemical reaction will be:

Explanation :
Single replacement reaction : A chemical reaction in which the more reactive element replace the less reactive element.
It is represented as,

In this reaction, A is more reactive element and B is less reactive element.
As per question, when gold (IV) iodide react with bromine to give gold (IV) bromide and iodine.
The balanced chemical reaction will be:

5.60*10²³ is the answer First you find the molar mass of nickel then you you turn grams to moles to atoms and boom there's your answer.
C. Chemical properties always change depending on temperature or pressure
Explanation:
Reaction rate is a measure of speed of a chemical reaction.
Usually, based on rates, reactions can be divided into two parts:
- Slow reactions which usually takes a long time.
- Fast reactions which takes place completely in seconds or microseconds.
Reaction rate can be defined as a change in the concentration of a reactant or product per unit time:
The unit is mol dm⁻³ s⁻¹
Reaction rate = 
The measurement of the reaction rate is based on the disappearance of a reactant or appearance of a product with increasing reaction time.
Learn more:
Reaction rate brainly.com/question/9642960
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