Answer:
The correct answer is: d. The pKa of the chosen buffer should be close to the optimal pH for the biochemical reaction.
Explanation:
The buffer resist or maintain the change in pH in case of Acid or basic addition to the solution. The buffer capacity should be within one or two pH units when compared to the optimal pH.
Thus it is important to select a buffer with pKa close to the optimum pH of the reaction because the ability for the buffer to maintain the pH is is great at the pH close to pKa.
Wind ,ice,and water eroded it over years
Answer: 2800 calories
Explanation:
Latent heat of fusion is the amount of heat required to convert 1 mole of solid to liquid at atmospheric pressure.
Amount of heat required to fuse 1 gram of water = 80 cal
Mass of ice given = 35 gram
Heat required to fuse 1 g of ice at
= 80 cal
Thus Heat required to fuse 35 g of ice =
Thus 2800 calories of energy is required to melt 35 g ice cube
Answer:
7.98 × 10^3grams.
Explanation:
To find the mass of fluorine in the number of atoms provided, we first divide the number of atoms by Avagadros number (6.02 × 10^23atoms) to get the number of moles in the fluorine atom. That is;
number of moles (n) = number of atoms (nA) ÷ 6.02 × 10^23 atoms
n = 2.542 × 10^26 ÷ 6.02 × 10^23
n = 0.42 × 10^ (26-23)
n = 0.42 × 10^3
n = 4.2 × 10^2moles
Using mole = mass ÷ molar mass
Molar/atomic mass of fluorine (F) = 19g/mol
mass = molar mass × mole
Mass (g) = 19 × 4.2 × 10^2
Mass = 79.8 × 10^2
Mass = 7.98 × 10^3grams.
140 s. It would take 140 s to swim 0.150 mi
.
<em>Step 1</em>. Convert the <em>time to seconds</em>
Time = 14 min × (60 s/1 min) + 34.56 s = 840 s + 34.56 s = 874.56 s
<em>Step 2</em>. Convert <em>miles to metres
</em>
Distance = 0.150 mi × (1609.3 m/1 mi) = 241.4 m
<em>Step 3.</em> Calculate the <em>time to swim 241.4 m</em>
Time = 241.4 m × (874.56 s/1500 m) = 140 s
(<em>As of 2012, the men’s freestyle record for 1500 m was 14:31.02</em>.)