<span>Answer:
Moles Ca(NO3)2 = 100 x 0.250 / 1000 = 0.025
Ca(NO3)2 >> Ca2+ + 2NO3-
Moles NO3- = 2 x 0.025 = 0.05
Moles HNO3 = 400 x 0.100 / 1000 = 0.04
Total moles = 0.05 + 0.04 = 0.09
Total volume = 500 ml = 0.500 L
M = 0.09 / 0.500 = 0.18</span>
Answer: 0.24 moles
Explanation:
Molecular Mass of NaCl (23 + 35.5) = 58.5g
58.5g of Sodium Chloride -------> 1 mole of NaCl
∴ 13.8g of Sodium Chloride ------> 1 ÷58.5 x 13.8 = 0.2358974 ≈ 0.24moles
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Answer:
A 1 liter volumetric flask should be used.
Explanation:
First we <u>convert 166.00 g of KI into moles</u>, using its <em>molar mass</em>:
Molar mass of KI = Molar mass of K + Molar mass of I = 166 g/mol
- 166.00 g ÷ 166 g/mol = 1 mol KI
Then we <u>calculate the required volume</u>, using the <em>definition of molarity</em>:
- Molarity = moles / liters
Liters = moles / molarity
Answer:
3.46x10⁴
Explanation:
Hello,
In this case, we can see that the number 34,560 has five significant figures, it means that if we want to write it with three, we must take the 3, 4 and 5 only. Nevertheless, since the 6 after the five is greater than 5, we can round such five to 6, so we obtain:
346
However, the decimal places cannot get lost, therefore, we move the given thousand to the three, so the number turns out:
3.46x10⁴
Best regards.
We write DE = q+w, where DE is the internal energy change and q and w are heat and work, respectively.
(b)Under what conditions will the quantities q and w be negative numbers?
q is negative when heat flows from the system to the surroundings, and w is negative when the system does work on the surroundings.
As an aside: In applying the first law, do we need to measure the internal energy of a system? Explain.
The absolute internal energy of a system cannot be measured, at least in any practical sense. The internal energy encompasses the kinetic energy of all moving particles in the system, including subatomic particles, as well as the electrostatic potential energies between all these particles. We can measure the change in internal energy (DE) as the result of a chemical or physical change, but we cannot determine the absolute internal energy of either the initial or the final state. The first law allows us to calculate the change in internal energy during a transformation by calculating the heat and work exchanged between the system and its surroundings.
