The equation for energy of a photon is E=hv where v equals frequency and h equals the Planck constant (6.626X10^-34). So since you've been given frequency you can just plug in frequency to find the total energy in joules.
E=(3.55X10^17)(6.626X10^-34)
E=2.35223X10^-16
Not sure how many significant figures you needed. Hope this helped.
According to the calculation, set I is both the most accurate and most precise.
Exactness is a quality or state of being precise. 2a: comparison accuracy sense: the degree of precision with which an action is carried out or a measurement expressed 2b. The novel was fact-checked for historical authenticity. 2a: conformance to truth, to a standard, or to a model: exactness It is impossible to estimate the number of casualties with accuracy. Let's calculate the precision for the fourth set, considering
Δ1 = ∣(8.41−8.56)∣ g=0.15 g
Δ2 = (8.72−8.56) g=0.16 g
Δ3 = ∣(8.55−8.56)∣ g=0.01 g
Therefore: 
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<h3><u>Answer;</u></h3>
0.5 M HBr, pOH = 13.5 ; Has the lowest pH
<h3><u>Explanation;</u></h3>
From the question;
pH = -Log [OH]
or pH = 14 - pOH
Therefore;
For 0.5 M HBr
[H+] = 0.5 M
pH = - Log [0.5]
= 0.30
For; pOH = 13.5
pH = 14 - pOH
= 14 -13.5
= 0.5
For; 0.05 M HCl
pH = - log [H+]
[H+] = 0.05
pH = - Log [0.05]
= 1.30
For; pOH = 12.7
pH = 14 -pOH
= 14 -12.7
= 1.30
For; 0.005 M KOH,
pOH = - log [OH]
[OH-] = 0.005
pOH = - Log 0.005
= 2.30
pH = 14 - 2.30
= 11.7
For; pOH = 2.3
pH = 14 -pOH
= 14- 2.3
= 11.7
Carbon -13 has 7 neutrons and carbon -12 has six neutrons. Carbon -12 is the most common isotope of Carbon. Carbon -14 is radioactive and vary rare. The symbols for the isotopes of Carbon atoms shown here indicate they each have six protons but mass numbers of 14, 13, and 12. Hope this helps. :)
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\%
glad to help you
hope it helps
