Answer:
0.550
Explanation:
The absorbance (A) of a substance depends on its concentration (c) according to Beer-Lambert law.
A = ε . <em>l</em> . c
where,
ε: absorptivity of the species
<em>l</em>: optical path length
A 45 mM phosphate solution (solution A) had an absorbance of 1.012.
A = ε . <em>l</em> . c
1.012 = ε . <em>l</em> . 45 mM
ε . <em>l</em> = 0.022 mM⁻¹
We can find the concentration of the second solution using the dilution rule.
C₁ . V₁ = C₂ . V₂
45mM . 11mL = C₂ . 20.0 mL
C₂ = 25 mM
The absorbance of the second solution is:
A = (ε . <em>l</em> ). c
A = (0.022 mM⁻¹) . 25 mM = 0.55 (rounding off to 3 significant figures = 0.550)
Answer:
1. Mass of potassium (K) = 203.32 g
2. Number of mole of As = 7.53 moles
Explanation:
1. Determination of the mass of potassium (K)
Molar mass of K = 39.1 g/mol
Number of mole of K = 5.2 moles
Mass of K =.?
Mole = mass / Molar mass
5.2 = mass of K / 39.1
Cross multiply
Mass of K = 5.2 × 39.1
Mass of potassium (K) = 203.32 g
2. Determination of the number of mole of Arsenic (As)
Molar mass of As = 74.92 g/mol
Mass of As = 563.9 g
Number of mole of As =.?
Mole = mass /Molar mass
Number of mole of As = 563.9 / 74.92
Number of mole of As = 7.53 moles
Answer:
Order zero
Explanation:
Let's consider the decomposition of ammonia to nitrogen and hydrogen on a tungsten filament at 800°C.
2 NH₃(g) → N₂(g) + 3 H₂(g)
The generic rate law is:
rate = k × [NH₃]ⁿ
where,
rate: reaction rate
k: rate constant
n: reaction order
When n = 0, we get:
rate = k × [NH₃]⁰ = k
As we can see, when the reaction order with respect to ammonia is zero, the reaction rate is independent of the concentration of ammonia.
Answer:
E
Explanation:
burning a substance changes it chemically.
Answer:14.93
Explanation:heat gained=heat lost
120.5 ×4.184×change=7525
7525÷504.172
Ans14.925