<span>The half-life of a first-order reaction is determined as follows:
</span>t½<span>=ln2/k
From the equation, we can calculate the </span><span>first-order rate constant:
</span>k = (ln(2)) / t½ = 0.693 / 90 = 7.7 × 10⁻³
When we know the value of k we can then calculate concentration with the equation:
A₀ = 2 g/100 mL
t = 2.5 h = 150min
A = A₀ × e^(-kt) =2 × e^(-7.7 × 10⁻³ × 150) = 0.63 g / 100ml
= 6.3 × 10⁻⁴ mg / 100ml
Answer:
1) The atomic number of this element is 74, because number of protons = atomic number
2) Mass number of this element is 184
Ar=Z+N=74+110=184
3) It isn't a new element. An element with such atomic and mass numbers exists
4) It is Wolfram. Symbol: W
5) Solid
Sorry if I made mistakes. I started learning English recently.
Answer:
The correct option is: B) H₂0 and OH⁻ as a conjugate pair
Explanation:
According to Brønsted-Lowry theory, the<u> </u><u>acids</u><u> are the chemical substances that form a conjugate base by donating a proton</u> and <u>bases</u><u> are the chemical substances that form conjugate acid by accepting a proton.</u>
In the given chemical reaction: PO₄³⁻(aq) + H₂O(l) ⇄ HPO₄²⁻(aq) + OH⁻(aq)
<u>According to Brønsted-Lowry theory, PO₄³⁻ and OH⁻ are bases. Whereas, H₂O and HPO₄²⁻ are acids.</u>
<u>Also, PO₄³⁻ and HPO₄²⁻ are the conjugate acid-base pair; and H₂O and OH⁻ are the conjugate acid-base pair.</u>
