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2 years ago

A sample of air has a volume of 140.0 mL at 67C. To w

Chemistry

1 answer:

bonufazy [111]2 years ago

7 0

Answer:

What that means is that when pressure and number of moles are kept constant, increasing the temperature will result in an increase in volume. Likewise, a decrease in temperature will result in a decrease in volume. In your case, the volume of the gas decreased by a factor of about 3, from "140.0 mL" to "50.0 mL".

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PLEASE HELP ME ASAP!

uranmaximum [27]

your answer is b hope this helps

7 0

2 years ago

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A buffer solution is composed of 1.00 mol of acid and 2.25 mol of the conjugate base. If the p K a of the acid is 4.90 , what is

Gemiola [76]

Answer: The pH of the buffer is 5.25

Explanation:

Let the volume of buffer solution be V

We know that:

$\text{Molarity}=\frac{\text{Moles of solute}}{\text{Volume of solution}}$

To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:

$pH=pK_a+\log(\frac{[\text{conjugate base}]}{[acid]})$

We are given:

$pK_a$ = negative logarithm of acid dissociation constant of weak acid = 4.90

$[\text{conjugate base}]=\frac{2.25}{V}$

$[acid]=\frac{1.00}{V}$

pH = ?

Putting values in above equation, we get:

$pH=4.90+\log(\frac{2.25/V}{1.00/V})\\\\pH=5.25$

Hence, the pH of the buffer is 5.25

4 0

2 years ago

Water has a density of 1.0 g/cm3. Glycerin, a liquid used in some soaps, has a density of 1.26 g/cm3. If an object sinks in wate

sdas [7]

For an object to sink in something, it's density has to be higher than the object it is in, so if it sinks in water the number has be higher than 1

And to float, and objects density has to be lower than that of the substance it is put in, so it has to be lower than 1.26

So between 1 and 1.26

5 0

2 years ago

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Acetylene gas is often used in welding torches because of the very high heat produced when it reacts with oxygen gas, producing

rodikova [14]

Answer:

0.225 mol = 0.23 mol to 2 significant figures

Explanation:

Calculate the moles of oxygen needed to produce 0.090 mol of water

The equation of the reaction is given as;

2 C2H2 + 5 O2 --> 4 CO2 + 2 H2O

From the equation of the reaction;

5 mol of O2 produces 2 mol of H2O

x mol of O2 produces 0.090 mol of H2O

5 = 2

x = 0.090

x = 0.090 * 5 / 2

x = 0.225 mol

8 0

2 years ago

2.00 L of 0.800 M NaNO3 must be prepared from a solution known to be 2.50 M in concentration.How many mL are required? Plus don'

Morgarella [4.7K]

Answer:

1.36 × 10³ mL of water.

Explanation:

We can utilize the dilution equation. Recall that:

$\displaystyle M_1V_1= M_2V_2$

Where M represents molarity and V represents volume.

Let the initial concentration and unknown volume be M₁ and V₁, respectively. Let the final concentration and required volume be M₂ and V₂, respectively. Solve for V₁:

$\displaystyle \begin{aligned} (2.50\text{ M})V_1 &= (0.800\text{ M})(2.00\text{ L}) \\ \\ V_1 & = 0.640\text{ L} \end{aligned}$

Therefore, we can begin with 0.640 L of the 2.50 M solution and add enough distilled water to dilute the solution to 2.00 L. The required amount of water is thus:
$\displaystyle 2.00\text{ L} - 0.640\text{ L} = 1.36\text{ L}$

Convert this value to mL:
$\displaystyle 1.36\text{ L} \cdot \frac{1000\text{ mL}}{1\text{ L}} = 1.36\times 10^3\text{ mL}$

Therefore, about 1.36 × 10³ mL of water need to be added to the 2.50 M solution.

8 0

1 year ago