The correct answer would be the fourth option. A nucleotide consists of a phosphate group, a pentose sugar, and a nitrogen containing base that are all linked together by covalent bonds. Nucleotides are the monomer units of nucleic acids and is the basic unit of the DNA.
Elements in group 1-2, 13-18, the number of valence electrons is related to the group number. For example, in the first group, the alkali metals there is one valence electron, however in group 13, there are 3 valence electrons. Valence electrons are also known as the outershell electrons.
Answer:
The biological significance is that it is the normal human body temperature and also the optimum temperature of the enzyme.
Explanation:
- Enzymes are biological catalysts that speed up the rate of chemical reactions.
- Enzymes catalyze specific reactions by working on a specific substrate to convert it into a product.
- The rate of enzyme activity depends on several factors which include pH, temperature, substrate concentration, and enzyme concentration among others.
- Enzymes work best at a specific pH and temperature known as optimum pH and optimum temperature respectively.
- In this case, enzyme amylase works best at a temperature of 37° C which is equivalent to the normal human body temperature.
<u>Question:</u>
For the cell constructed from the hydrogen electrode and metal-insoluble salt electrode, B) calculate the mean activity coefficient for 0.124 b HCl solution if E=0.342 V at 298 K
<u>Answer:</u>
The mean activity coefficient for HCl solution is 0.78.
<u>Explanation:</u>
Activity coefficient is defined as the ratio of any chemical activity of any substance with its molar concentration. So in an electrochemical cell, we can write activity coefficient as γ. The equation for determining the mean activity coefficient is
As we know that 
= 0.22 V and E = 0.342 V, the equation will become
So, the mean activity coefficient is 0.78.
The number of atoms of K that are in 235 g of the compound is
2.57 x10^24 atoms
calculation
Step 1: find the moles of K2S
= moles = mass/molar mass
= 235 g/110 g/mol= 2.136 moles
Step 2: multiply 2.136 moles by no. of K atoms in K2S
= 2.136 x2 = 4.272 moles
Step 3: use the Avogadro's law to determine number of K atoms
that is according to Avogadro's law 1 mole = 6.02 x 10^23 atoms
4.272 moles= ? atoms
by cross multiplication
= (4.272 moles x 6.02 x10^23 atoms) / 1 mole = 2.57 x10^24 atoms
