Answer:
648.68 mg
Explanation:
The reaction that takes place is:
- FeCl₃ + 3NaOH → Fe(OH)₃ + 3NaCl
First we<u> calculate how many moles of each reactant were added</u>, using the <em>given volumes and concentrations</em>:
- FeCl₃ ⇒ 100 mL * 0.240 M = 24 mmol FeCl₃
- NaOH ⇒ 100 mL * 0.182 M = 18.2 mmol NaOH
24 mmol of FeCl₃ would react completely with (24 * 3) 72 mmol of NaOH. There are not as many NaOH mmoles, so NaOH is the limiting reactant.
Now we <u>calculate how many moles of Fe(OH)₃ are formed</u>, using the <em>moles of the limiting reactant</em>:
- 18.2 mmol NaOH *
= 6.07 mmol Fe(OH)₃
Finally we <u>convert 6.07 mmol Fe(OH)₃ to grams</u>, using its<em> molar mass</em>:
- 6.07 mmol Fe(OH)₃ * 106.867 mg/mmol = 648.68 mg
Based on the ideal gas relation:
PV = nRT
where P = pressure ; V = volume ; T = temperature
n = number of moles; R = gas constant = 0.0821 L atm/mol-K
Step 1: Find the number of moles of O2
n = PV/RT = 1 * 3.90/0.0821*273 = 0.1740 moles
Step 2: Calculate the molecules of O2
Now, 1 mole of O2 corresponds to 6.023 * 10²³ molecules of O2
Therefore, 0.1740 moles of O2 corresponds to-
0.1740 moles of O2 * 6.023*10²³ molecules of O2/1 mole of O2
= 1.048 * 10²³ molecules of O2
When salt water is added to onion cells, then the cells will lose water due to osmosis, this can be observed.
Liquid crystal molecules have very unique structures, allowing them to be highly affected by electric fields, changing their orientation in the liquid crystal structure. This is why they are used in LCD screens. They are also highly sensitive to changes in temperature. Therefore the answer is C.
Hope this helps!
Answer is: it takes 116,8 seconds to fall to one-sixteenth of its initial value
<span>
The half-life for the chemical reaction is 29,2 s and is
independent of initial concentration.
c</span>₀
- initial concentration the reactant.
c - concentration of the reactant remaining
at time.
t = 29,2 s.<span>
First calculate the rate constant k:
k = 0,693 ÷ t = 0,693 ÷ 29,2 s</span> = 0,0237 1/s.<span>
ln(c/c</span>₀) = -k·t₁.<span>
ln(1/16 </span>÷ 1) = -0,0237 1/s ·
t₁.
t₁ = 116,8 s.
