What happens to temperature as a substance melts and heat energy is used to break the connections between molecules, until all melting is complete?.
Answer : Stays the same
The reaction between C2H2 and O2 is as follows:
2C2H2 + 5O2 = 4CO2 + 2H2O
After balancing the equation, the reaction ratio between C2H2 and O2 is 2:5.
The moles of O2 in this reaction is 84.0 mol. According to the above ratio, the moles of C2H2 needed to react completely with the O2 is 84.0mole *2/5 = 33.6 mole.
The pH of a neutral aqueous solution at 37°C is 6.8.
<h3>What is Kw? </h3>
Kw is defined as the dissociation, which is also known as self-ionization, constant of water. this is an equilibrium constant, and its expression is:
Kw = [OH⁻] . [H₃O⁺]
Neutral pH determines that the concentrations of OH⁻ and H₃O⁺ are equal.
<h3>Calculation</h3>
Let us suppose concentration of OH and H₃O⁺ is x, to calculate it:
Kw =[OH⁻] . [H₃O⁺] = x²
x² = 2.4 × 10⁻¹⁴ M²
x = 1.5919 × 10⁻⁷ M
Hence, the concentration of OH and H₃O⁺ (x) = [H₃O⁺] = [OH⁻] = 1.5919×10⁻⁷ M
pH = -log[H₃O⁺] = -log( 1.5919×10⁻⁷ M)
pH = 6.8
Thus, we find that the pH of a neutral aqueous solution at 37 °c (which is the normal human body temperature) is 6.8.
learn more about pH:
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Answer:
4
Explanation:
Speed=Distance/time, so 20/5 divide time divided by distance. so the answer is 4.
