The internal energy has the symbol U. Q is positive if heat is added to the system, and negative if heat is removed;
....."W is positive if work is done by the system"........
and negative if work is done on the system.
So, work done by a system is positive.
Answer:
0.200M H₃PO₄
0.600N H₃PO₄
pH = 1.46
Explanation:
The acid-base reaction of phosphoric acid (H₃PO₄) with LiOH is:
3 LiOH + H₃PO₄ → Li₃PO₄ + 3H₂O
<em>Where 3 moles of LiOH reacts per mole of H₃PO₄</em>
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Moles of LiOH are:
0.030L× (0.5mol / L) = 0.0150 moles of LiOH
Moles of acid neutralized are:
0.0150 moles of LiOH × (1 mole H₃PO₄ / 3 moles LiOH) = 0.005 moles H₃PO₄
As volume of acid was 25mL, molarity is:
0.005mol H₃PO₄ / 0.025L =<em> 0.200M H₃PO₄</em>
Normality is:
0.200M × (3N H⁺ / 1M H₃PO₄) = <em>0.600N H₃PO₄</em>
H₃PO₄ dissolves in water thus:
H₃PO₄ ⇄ H₂PO₄⁻ + H⁺
Ka = 7.1x10⁻³ = [H₂PO₄⁻] [H⁺] / [H₃PO₄]
Where molar concentrations in equilibrium will be:
[H₂PO₄⁻] = X
[H⁺] = X
[H₃PO₄] = 0.200M - X
Replacing in Ka formula:
7.1x10⁻³ = [X] [X] / [0.200 - X]
1.42x10⁻³ - 7.1x10⁻³X = X²
0 = X² + 7.1x10⁻³X - 1.42x10⁻³
Solving for X:
X = -0.04M →False answer, there is no negative concentrations.
X = 0.0343M
As, [H⁺] = 0.0343M
pH = - log [H⁺],
<em>pH = 1.46</em>
Answer:
grapefruit juice is an acid
Explanation:
A piece of neutral litmus paper turned red in some grapefruit juice. What does this show about the grapefruit juice
with litmus paper remember:
E R
S E
ACID
BLUE
acids turn litmus red, bases turn it blue
all citrus fruits :llemons, lime, grapefruit, oranges, etc are called
CITRUS FRUITS because they contain citric acid
The answer is A, you must repeat your experiment to ensure you results are accurate. That is the best way to know for sure and it is what you must do to every experiment.
Answer:
the answer is d hope this helps
and dont forget to mark me as brainliest
Explanation:
