Answer:
1.10 × 10⁻¹² m
General Formulas and Concepts:
<u>Chemistry - Atomic Structure</u>
Speed of Light = Wavelength times Frequency
Explanation:
<u>Step 1: Define</u>
ν = 2.73 × 10²⁰ Hz
<u>Step 2: Find wavelength</u>
3.0 × 10⁸ m/s = λ(2.73 × 10²⁰ Hz)
λ = 1.0989 × 10⁻¹² m
<u>Step 3: Check</u>
<em>We are given 3 sig figs. Follow sig fig rules.</em>
1.0989 × 10⁻¹² m ≈ 1.10 × 10⁻¹² m
Answer:
(3) 5.36
Explanation:
Since this is a titration of a weak acid before reaching equivalence point, we will have effectively a buffer solution. Then we can use the Henderson-Hasselbalch equation to answer this question.
The reaction is:
HAc + NaOH ⇒ NaAc + H₂O
V NaOH = 40 mL x 1 L/1000 mL = 0.040 L
mol NaOH reacted with HAc = 0.040 L x 0.05 mol/L = 0.002 mol
mol HAC originally present = 0.050 L x 0.05 mol/L = 0.0025 mol
mol HAc left after reaction = 0.0025 - 0.002 = 0.0005
Now that we have calculated the quantities of the weak acid and its conjugate base in the buffer, we just plug the values into the equation
pH = pKa + log ((Ac⁻)/(HAc))
(Notice we do not have to calculate the molarities of Ac⁻ and HAc because the volumes cancel in the quotient)
pH = -log (1.75 x 10⁻⁵) + log (0.002/0.0005) = 5.36
THe answer is 5.36
Atomic number
atomic mass
group|family
periods
and element symbols
<span>the atom that has these characteritics is called beryllium nucleus</span>
That statement is true
it was easy to organize 'all' the elements in a group of threes because back then they only knew about 15 - 20 elements
hope this helps
