Answer:
exothermic reaction
Explanation:
I think this because this is an example of an exothermic reaction is the chemical reaction between sodium and chlorine, which results in the formation of sodium chloride (also known as common salt)
Answer:
E
C
B
D
A
Explanation:
The definition of words correspond well with the answers I provided and somewhat match with the dictionary definitions.
A: making s sandcastle. This is because water and sand is only a mixture, so they do not react with each other. All the rest include chemical reactions!
Answer:
D. 0.75 grams
Explanation:
The data given on the iridium 182 are;
The half life of the iridium 182,
= 15 years
The mass of the sample of iridium, N₀ = 3 grams
The amount left, N(t) after two half lives is given as follows;

For two half lives, t = 2 × 
∴ t = 2 × 15 = 30


∴ The amount left, N(t) = 0.75 grams
Answer:
6.02*10^23
Explanation:
This is the number for one mole. Just like one dozen = 12, one mole = 6.02*10^23.
Fun fact, if you had a mole of pennies you could spend 1 million dollars every second of your life and not have even spent 1% of it by the time you die at 100 years old.