Which statement about proteins is true?
2 answers:
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Explanation:
Atomic mass means the sum of total number of protons and neutrons present in an atom.
When an atom is neutral then number of protons equal the number of electrons.
Mass of a proton equals to 1.007276 u, mass of neutron equals to 1.008664 u.
For example, in a atom there are total 9 protons and number of neutrons is 19 - 9 = 10.
Since, it is a neutral atom so number of electrons will also be 9.
So, total mass will be calculated as follows.
Total mass = 9 (mass of electron + mass of proton)
= 9 (1.007825 u)
= 9.07043 u
Therefore, we can conclude that total mass of protons and electrons in is 9.07043 u.
Answer:
0.64 M
Explanation:
Given:
Volume of iron(II) solution (V₁) = 25.0 mL = 0.025 L
Molarity of iron(II) solution (M₁) = ?
Number of moles of iron(II) solution (n₁) = ?
Volume of dichromate solution (V₂) = 18.0 mL = 0.018 L
Molarity of dichromate solution (M₂) = 0.145 M
Number of moles of dichromate solution (n₂) = ?
Molarity is equal to the ratio of moles and volume.
So, molarity of dichromate solution is given as:
Now, let us write the complete balanced reaction for the given situation.
So, the complete balanced equation is given below.
From the equation, it is clear that, 1 mole of dichromate is required for 6 moles of iron(II) solution.
So, using unitary method, we find the number of moles of iron(II) solution.
1 mole of dichromate = 6 moles of iron(II)
∴ n₂ moles of dichromate = 6n₂ moles of iron(II)
=
So, 0.016 moles of iron(II) is needed. Therefore,
Now, molarity of iron(II) solution is given as:
Molarity = Moles ÷ Volume
Therefore, the molarity of the iron(II) solution is 0.64 M.