Answer:
A) Melting
Explanation:
The three changes of phase described in this problem are:
- Melting: melting occurs when a substance in solid state turns into liquid state. Since molecules in liquid state have more energy than molecules in solid state (because in liquids, molecules can slide past each other, while in solids they can't move, but only vibrate), thermal energy must be added in order to melt a substance
- Freezing: freezing occurs when a liquid substance turns into solid state (the opposite of melting). Since molecules in liquid state have more energy than molecules in solid state, thermal energy must be removed from the substance in order to cause freezing
- Condensation: condensation occurs when a gaseous substance turns into liquid state. Since molecules in gaseous state have more energy than molecules in liquid state, thermal energy must be removed from the substance in order to cause condensation
So the correct option is
A) melting
Answer:
a) pH = 13.176
b) pH = 13
c) pH = 12.574
d) pH = 7.0
e) pH = 1.46
f) pH = 1.21
Explanation:
HBr + NaOH ↔ NaBr + H2O
∴ equivalent point:
⇒ mol acid = mol base
⇒ (Va)*(0.150mol/L) = (0.025L)*(0.150mol/L)
⇒ Va = 0.025 L
a) before addition acid:
⇒ <em>C </em>NaOH = 0.150 M
⇒ [ OH- ] = 0.150 M
⇒ pOH = - Log ( 0.150 )
⇒ pOH = 0.824
⇒ pH = 14 - pOH
⇒ pH = 13.176
b) after addition 5mL HBr:
⇒ <em>C </em>NaOH = (( 0.025)*(0.150) - (0.005)*(0.150)) / (0.025 + 0.005) = 0.1 M
⇒ <em>C </em>HBr = (0.005)*(0.150) / ( 0.03 ) = 0.025 M
⇒ [ OH- ] = 0.1 M
⇒ pOH = 1
⇒ pH = 13
c) after addition 15mL HBr:
⇒ <em>C </em>NaOH = ((0.025)*(0.150) - (0.015)*(0.150 ))/(0.04) = 0.0375 M
⇒ <em>C </em>HBr = ((0.015)*(0.150))/(0.04) = 0.0563 M
⇒ [ OH- ] = 0.0375 M
⇒ pOH = 1.426
⇒ pH = 12.574
d) after addition 25mL HBr:
equivalent point:
⇒ [ OH- ] = [ H3O+ ]
⇒ Kw = 1 E-14 = [ H3O+ ] * [ OH- ] = [ H3O+ ]²
⇒ [ H3O+ ] = 1 E-7
⇒ pH = 7.0
d) after addition 40mL HBr:
⇒ <em>C</em> HBr = ((0.04)*(0.150) - (0.025)*(0.150)) / (0.04 + 0.025) = 0.035 M
⇒ [ H3O+ ] = 0.035 M
⇒ pH = 1.46
d) after addition 60mL HBr:
⇒ <em>C</em> HBr = ((0.06)*(0.150) - (0.025)*(0.150)) / (0.06+0.025) = 0.062 M
⇒ [ H3O+ ] = 0.062 M
⇒ pH = 1.21
Answer:
20 + CIPb
Explanation:
Use the commutateive proptery to reoder the terms
All of the acid molecules in beaker 1 dissociate fully and exist as and ions. As a result, beaker 1 represents a strong acid solution. The majority of the molecules in beaker 2 are undissociated.
