Answer:
oxidation number is correct!! :)
Explanation:
The balanced chemical reaction for the described reaction above is,
Na2CO3 + 2HCl ---> 2NaCl + H2CO3
From the reaction, 1 mole of Na2CO3 is needed to produce 2 moles of NaCl. In terms of mass, 106 grams of Na2CO3 are needed to produce 116.9 grams of NaCl. From this,
(23.4 g NaCl) x (106 g Na2CO3 / 116.9 NaCl = 21.22 g Na2CO3
Thus, approximately 21.22 g Na2CO3 is needed for the desired reaction.
Answer:
The correct option is: A. activity; concentration
Explanation:
A reaction rate essay is a laboratory method to determine the activity of an enzyme. It is necessary for determining the enzyme kinetics and inhibition.
Whereas, a colorimetric analysis is a method to determine the concentration of a chemical compound in a solution. Therefore, a colorimetric endpoint assay measures the concentration.
Therefore, Enzyme activity is measured by a reaction rate assay and the concentration is measured by a colorimetric endpoint assay.
The half-life in months of a radioactive element that reduce to 5.00% of its initial mass in 500.0 years is approximately 1389 months
To solve this question, we'll begin by calculating the number of half-lives that has elapsed. This can be obtained as follow:
Amount remaining (N) = 5%
Original amount (N₀) = 100%
<h3>Number of half-lives (n) =?</h3>
N₀ × 2ⁿ = N
5 × 2ⁿ = 100
2ⁿ = 100/5
2ⁿ = 20
Take the log of both side
Log 2ⁿ = log 20
nlog 2 = log 20
Divide both side by log 2
n = log 20 / log 2
<h3>n = 4.32</h3>
Thus, 4.32 half-lives gas elapsed.
Finally, we shall determine the half-life of the element. This can be obtained as follow.
Number of half-lives (n) = 4.32
Time (t) = 500 years
<h3>Half-life (t½) =? </h3>
t½ = t / n
t½ = 500 / 4.32
t½ = 115.74 years
Multiply by 12 to express in months
t½ = 115.74 × 12
<h3>t½ ≈ 1389 months </h3>
Therefore, the half-life of the radioactive element in months is approximately 1389 months
Learn more: brainly.com/question/24868345
Answer:
Examples of substances insoluble in water: oil, acetone, ether
Explanation:
Such examples of substances are non-polar and do not dissolve in water (polar compound). The classic example is oil floating in water (this happens because oil has a lower density than water).
