Answer:
0.56
Explanation:
From the formula;
0.693/t1/2 = 2.303/t log (Ao/At)
t1/2 = half life of the C-14 = 5730 y
t = time elapsed = 4800 y
At = Activity of C-14 at time t
Ao= Activity of a living C-14 sample
0.693/5730 = 2.303/4800 log (Ao/At)
1.2 * 10^-4 = 4.8 * 10^-4 log (Ao/At)
log (Ao/At) = 1.2 * 10^-4/4.8 * 10^-4
log (Ao/At) = 0.25
Ao/At = Antilog (0.25)
Ao/At = 1.778
Hence;
At/Ao = (1.778)^-1
At/Ao = 0.56
Answer: a. It receives a hydrogen ion.
Explanation: Base is a species which is capable of donating its negative quantity and accepting the positive one.
For example, ammonia is considered as a base because it is capable of donating its lone pairs of electrons and can accept an proton as well.
Here, out of the given options, Hydrogen 
is a proton which is acting as a positive species and hydroxide ion 
is a negative species.
Thus, option (A) is the correct answer as it will receive a hydrogen ion from another base making itself a conjugate acid.
Answer:
The mass of oxygen gas required to produce 65.75 grams of steam is approximately 162.2 grams
Explanation:
From the question, we have the following chemical reaction equation;
2C₃H₁₈(l) + 25O₂ (g) → 16CO₂(g) + 18H₂O (g)
The molar mass of oxygen, O₂ = 32 g/mol
The molar mass of steam, H₂O = 18.01528 g/mol
25 moles of oxygen are required to produce 18 moles of steam
Therefore, according to Proust's law of definite proportions;
(32 × 25) g of oxygen are required to produce (18 × 18.01528) g of steam
65.75 g of steam will be produced by (32 × 25)/(18 × 18.01528) × 65.75 g ≈ 162.2 g of oxygen O₂.
The answer is B, this is a synthesis reaction. A good way to identify a synthesis reaction is when there are multiple reactants, but only one product.
