The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present).
Movement Across a Membrane and Energy. There are two major ways that molecules can be moved across a membrane, and the distinction has to do with whether or not cell energy is used. Passive mechanisms like diffusion use no energy, while active transport requires energy to get done.
Answer:
3.861x10⁻⁹ mol Pb⁺²
Explanation:
We can <u>define ppm as mg of Pb²⁺ per liter of water</u>.
We<u> calculate the mass of lead ion in 100 mL of water</u>:
- 100.0 mL ⇒ 100.0 / 1000 = 0.100 L
- 0.100 L * 0.0080 ppm = 8x10⁻⁴ mg Pb⁺²
Now we <u>convert mass of lead to moles</u>, using its molar mass:
- 8x10⁻⁴ mg ⇒ 8x10⁻⁴ / 1000 = 8x10⁻⁷ g
- 8x10⁻⁷ g Pb²⁺ ÷ 207.2 g/mol = 3.861x10⁻⁹ mol Pb⁺²
If a non-volatile sugar is added to water , the vapor pressure of liquid will tend to decreases and this reduction of vapor pressure is said to be proportional to the numbers of mole fraction of solute that was added to it.
<h3>What occurs when a non volatile solute is added to a solution?</h3>
In the case above, the vapor pressure of the solution is known to be lowered if compared to the vapor pressure of the pure solution.
Therefore if a non-volatile solute is said to be place or added to a pure solution such as water, the vapor pressure of the solution will be reduced than that of the pure solution.
Hence, the statement that If a non-volatile sugar is added to water , the vapor pressure of liquid will tend to decreases and this reduction of vapor pressure is said to be proportional to the numbers of mole fraction of solute that was added to it is correct.
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