The answer is A. Nitrogen Oxide
The fraction of the original amount remaining is closest to 1/128
<h3>Determination of the number of half-lives</h3>
- Half-life (t½) = 4 days
- Time (t) = 4 weeks = 4 × 7 = 28 days
- Number of half-lives (n) =?
n = t / t½
n = 28 / 4
n = 7
<h3>How to determine the amount remaining </h3>
- Original amount (N₀) = 100 g
- Number of half-lives (n) = 7
- Amount remaining (N)=?
N = N₀ / 2ⁿ
N = 100 / 2⁷
N = 0.78125 g
<h3>How to determine the fraction remaining </h3>
- Original amount (N₀) = 100 g
- Amount remaining (N)= 0.78125 g
Fraction remaining = N / N₀
Fraction remaining = 0.78125 / 100
Fraction remaining = 1/128
Learn more about half life:
brainly.com/question/26374513
This technique can be used to make pure crystals of a soluble salt.
The burette is filled with hydrochloric acid.
A known quantity of alkali (say 50 cm3 sodium hydroxide)
is released from a pipette into the conical flask.
The tap on the burette is turned open to allow
the acid to be added drop by drop into the alkali.
The alkali contains an indicator (phenolphthalein)
which is pink in an alkali and colorless in an <span>acid.
</span>
When enough acid has been added to neutralize
the alkali, the indicator changes from
pink to colorless. This is the end point of the titration.
The titration<span> can be repeated using the </span><span>same amounts
</span><span>of </span>acid<span> and </span>alkali<span> but </span>without<span> the </span>indicator.
<span>Pure salt</span> crystals<span> which are </span>free<span> from </span><span>indicator
</span><span>can then be crystallized </span><span> from the </span>neutral<span> solution.</span>
<span>The best and most correct answer among the choices provided by the question is the first choice. The characteristic that is primarily responsible for the existence of the rock ledge is its greater resistance to weathering. I hope my answer has come to your help. God bless and have a nice day ahead!</span>
Answer:
<u>2</u>H₂S + <u>1</u>O₂ → <u>2</u>H₂O + <u>2</u>S
Explanation:
<u>SOLUTION :-</u>
Balance it by using 'hit & trial' method , and you'll get the answer :-
<u>2</u>H₂S + <u>1</u>O₂ → <u>2</u>H₂O + <u>2</u>S
<u></u>
<u>VERIFICATION :-</u>
<em>In reactant side of equation :-</em>
- Number of atoms in H = 2×2 = 4
- Number of atoms in S = 2×1 = 2
- Number of atoms in O = 1×2 = 2
<em>In product side of equation :-</em>
- Number of atoms in H = 2×2 = 4
- Number of atoms in O = 2×1 = 2
- Number of atoms in S = 2×1 = 2
Number of atoms of each element is equal in both reactant & product side of equation. Hence , the equation is balanced.