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Which of the following gases will have the slowest rate of effusion at a given temperature?

borishaifa [10]

Answer: Argon (Ar).

Effusion is the escape of a gas through an opening considerably smaller than the mean free path of the molecules.

There is a formula that states that the rate of effusion is inversely proportional to the square root of the Molar Mass, at fixed temperature.

Then, the gas with the highest molar mass will have the lowest effusion rate.

Here are the molars masses of the four gases:

N2 = 2*14 g/mol= 28 g/mol

H2: 2 * 1g/mol = 2 g/mol

He: 4 g/mol

Ar: 40 g/mol

Then, Ar will exhibit the slowest rate of effusion at the same temperature.

7 0

3 years ago

The flask contains 10.0 mL of HCl and a few drops of phenolphthalein indicator. The buret contains 0.160 M NaOH. It requires 18.

olchik [2.2K]

Answer:

Approximately $0.291\; \rm M$ (rounded to two significant figures.)

Explanation:

The unit of concentration $\rm M$ is the same as $\rm mol \cdot L^{-1}$ (moles per liter.) On the other hand, the volume of both the $\rm NaOH$ solution and the original $\rm HCl$ solution here are in milliliters. Convert these two volumes to liters:

$V(\mathrm{NaOH}) = 18.2\; \rm mL = 18.2 \times 10^{-3}\; \rm L = 0.0182\; \rm L$ .
$V(\text{$\mathrm{HCl}$, original}) = 10.0\; \rm mL = 10.0\times 10^{-3}\; \rm L = 0.0100\; \rm L$ .

Calculate the number of moles of $\rm NaOH$ in that $0.0182\; \rm L$ of $0.160\; \rm M$ solution:

$\begin{aligned} n(\mathrm{NaOH}) &= c(\mathrm{NaOH})\cdot V(\mathrm{NaOH})\\ &= 0.160\; \rm mol \cdot L^{-1} \times 0.0182\; \rm L \approx 0.00291\; \rm mol\end{aligned}$ .

$\rm HCl$ reacts with $\rm NaOH$ at a one-to-one ratio:

$\rm HCl\; (aq) + NaOH\; (aq) \to NaCl\; (aq) + H_2O\; (l)$ .

Coefficient ratio:

$\displaystyle \frac{n(\mathrm{HCl})}{n(\mathrm{NaOH})} = 1$ .

In other words, one mole of $\rm NaOH$ would neutralize exactly one mole of $\rm HCl$ . In this titration, $0.291\; \rm mol$ of $\rm NaOH\!$ was required. Therefore, the same amount of $\rm HC$ should be present in the original solution:

$\begin{aligned}&n(\text{$\mathrm{HCl}$, original})\\ &= n(\mathrm{NaOH})\cdot \frac{n(\mathrm{HCl})}{n(\mathrm{NaOH})} \\ &\approx 0.00291\; \rm mol \times 1 = 0.00291\; \rm mol\end{aligned}$ .

Calculate the concentration of the original $\rm HCl$ solution:

$\displaystyle c(\text{$\mathrm{HCl}$, original}) = \frac{n(\text{$\mathrm{HCl}$, original})}{V(\text{$\mathrm{HCl}$, original})} \approx \frac{0.00291\; \rm mol}{0.0100\; \rm L} \approx 0.291\; \rm M$ .

5 0

3 years ago

A hydrate of iron (ii) sulfite is known to contain 44.26% mater. what is the correct name of the hydrate

stellarik [79]

The correct name of the hydrate iron (ii) sulfite is iron(ii)sulfite heptahydrate
it is gotten as below

find the % composition of FeSO4 = 100-44.26 =55.74 %

find the mole of FeSO4 and H20
= % composition/molar mass

FeSo4 =55.74/151.9 = 0.367 moles
H2O = 44.26/18 =2.459 moles

find the mole ratio by diving each mole with smallest mole
FeSO4 = 0.367/0.367 = 1
H2O = 2.459/0.367 = 7

therefore the name is iron (ii) sulfite heptahydrate is it has seven water molecules

6 0

4 years ago

How is wind energy captured?

Ainat [17]

Explanation:
How is wind energy captured?
= A wind turbine turns wind energy into electricity using the aerodynamic force from the rotor blades, which work like an airplane wing or helicopter rotor blade.
where is wind energy found?
= Location of U.S
how is water energy captured?
= Hydropower uses a fuel—water—that is not reduced or used up in the process. Because the water cycle is an endless, constantly recharging system, hydropower is considered a renewable energy.
where is water energy found?
= China, Canada, Brazil

5 0

3 years ago

I really need help in this...

Andrej [43]

5 is d because methane is a greenhouse gas
6 is a because it is a cause for global warming

6 0

3 years ago

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