Answer:
A machine have 75% efficiency means 25% of efficiency has been lost due to friction and a machine can work 75% only.
The average atomic weight is, from the name itself, the average weight of all its naturally occurring isotopes. All you have to do is multiple the abundance of each isotope with its individual mass, then add them altogether.
Mass = (0.10*55)+(0.15*56)+(.75*57)
<em>Mass = 56.65 amu</em>
Answer:
Mass of solution=100g
mass of salt=20g
so; mass of solute=80g
percentage composition =(mass of salt/total
mass) ×100
= \frac{20}{100} \times 100 \\ = 20\%
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For better representation, let me rewrite the electronic configuration:
<span>1s</span>²<span>2s</span>²<span>2p</span>⁶<span>3s</span>²<span>3p</span>⁶<span>4s</span>²<span>3d</span>⁴
The exponents represent the number of electrons in the designated subshell. Thus, the total number of electrons are:
# of electrons = 2+2+6+2+6+2+4 = 24
Assuming this is in neutral state, the element with an atomic number of 24 is Chromium. Thus, the answer is Cr.
[H_{3}O^{+}] = 0.00770 M
The equilibrium equation representing the dissociation of 
Given [H_{3}O^{+}] = 0.00770 M
Let the initial concentration of acid be x and change y
So y = ![[H_{3}O^{+}]](https://tex.z-dn.net/?f=%20%5BH_%7B3%7DO%5E%7B%2B%7D%5D%20%20%20)
=![[FCH_{2}COO^{-}]](https://tex.z-dn.net/?f=%20%5BFCH_%7B2%7DCOO%5E%7B-%7D%5D%20%20)
= 0.00770 M
0.00257 x - 0.00001979 = 0.00005929
x = 0.031 M
Therefore, initial concentration of the weak acid is <u>0.031 M</u>
