Answer:
42 days
Explanation:
Half life = 8.4 days
Starting mass = 40.0 g
Time = ?
Final Mass = 1/16 * 40 = 2.5 g
First Half life;
Remaining mass = 40 / 2 = 20g
Second Half life;
Remaining mass = 20 / 2 = 10g
Third Half life;
Remaining mass = 10 / 2 = 5g
Fourth Half life;
Remaining mass = 5 / 2 = 2.5g
Time = Number of half lives * Duration of half life = 5 * 8.4 = 42 days
The answer to your question is option b, a base. This is because the question clearly tells you that one reactant is an acid. Then, it tells you that an acid plus something gives you a salt and water, as products
From background knowledge, we know that a base plus acid gives you a salt and water. The hydroxide ions from the base neutralise the hydrogen ions from the acid, which gives you water ( as it has a pH of 7).
Therefore, your answer is b, a base
Answer:
30.4 g. NH3
Explanation:
This problem tells us that the hydrogen (H2) is the limiting reactant, as there is "an excess of nitrogen." Using stoichiometry (the relationship between the various species of the equation), we can see that for every 3 moles of H2 consumed, 2 moles of NH3 are produced.
But before we can use that relationship to find the number of grams of ammonia produced, we need to convert the given grams of hydrogen into moles:
5.4 g x [1 mol H2/(1.008x2 g.)] = 2.67857 mol H2 (not using significant figures yet; want to be as accurate as possible)
Now, we can use the relationship between H2 and NH3.
2.67857 mol H2 x (2 mol NH3/3 mol H2) = 1.7857 mol NH3
Now, we have the number of moles of ammonia produced, but the answer asks us for grams. Use the molar mass of ammonia to convert.
1.7857 mol NH3 x 17.034 g. NH3/mol NH3 = 30.4 g. NH3 (used a default # of 3 sig figs)
ANSWER: Increase
why? Because the number of C atoms in homologous series increases gradually.