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3 years ago

Chemistry help!!

Chemistry

1 answer:

Scrat [10]3 years ago

8 0

The student originally has 252 grams of water in this experiment.

LAW OF CONSERVATION OF MASS:

The law of conservation of mass explains that matter (mass) can neither be created nor destroyed but can be changed from one form to another.

This means that in a chemical reaction, the sum of the masses of the reactants must equate to the total mass of product(s).

According to this question, a student conducts an experiment to separate water into hydrogen and oxygen. The student collects 28.0 g of hydrogen and 224.0 g of oxygen.

Since hydrogen and oxygen are the constituent elements of water, the sum of their masses must equate the mass of water.

Therefore, 224g of oxygen + 28g of hydrogen = 252g of water.

Learn more at: brainly.com/question/24996173?referrer=searchResults

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Make a drawing of the particles in an NaCl solution to show why this solution conducts electricity. Make a drawing of the partic

cluponka [151]

Answer:

See the image attached. It is taken from an online chemistry textbook.

See the explanation below.

Explanation:

<em>Sodium chloride</em> consits of sodium cations (positive ions), Na⁺, and chloride anions (negative ions), CL⁻.

<u>Pure sodium chloride</u> is packed in crystals: sodium ions and chloride ions are packed together and the ions are in fixed positions. There are not free electrons that can move. Thus, sodium chloride doesn't conduct electricity, because there are no electrons or ions which are free to move.

In aqueous solution, sodium chloride units dissociates into their ions:

$NaCl\rightarrow Na^++Cl^-$

Those ions are freely to move in the solution, and such they are charge carriers, which conduct the electricity.

As explained above, in solid sodium chloride, the ions cannot move and there is not flow of current.

That is why solid pure salt of NaCl does not conduct electricity and the solutions of NaCl do conduct electricity.

The image attached show both diagrams. In the diagram A, the ions are packed together, showing that they cannot move. In the diagram B, the ions are dissolved in water, showing that they can move and carry the charge, allowing the flow of current.

5 0

3 years ago

Pure chlorobenzene is contained in a flask attached to an open-end mercury manometer. When the flask contents are at 58.3°C, the

Elan Coil [88]

Answer:

The slope is 4661.4K

(B), the intercept is 18.156

The vapor pressure of chlorobenzene is 731.4mmHg

The percentage of chlorobenzene originally in the vapor that condenses is = 99.7%

Explanation:

Two sets of conditions (a and b) are observed for L1 and L2 at two different temperatures.

$T_{a}$ = 58.3°C

$L1_{a}$ = 747mmHg

$L2_{a}$ = 52mmHg

$T_{b}$ = 110°C

$L1_{a}$ = 577mmHg

$L2_{b}$ = 222mmHg

We need to convert the temperatures from Celsius to Kelvin (K)

$T_{a}$ = 58.3°C + 273.2

$T_{a}$ = 331.5k

$T_{b}$ = 110°C + 273.2

$T_{b}$ = 383.2k

We then calculate the vapor pressures of the chlorobenzene at each set of conditions by measuring the difference in the mercury levels.

$P^{0}$ = $P_{atm} - (P_1 -P_2)$

The vapor pressure under the first set of conditions is:

$P^{a}$ = 755mmHg - (747mmHg - 52mmHg)

$P^{a}$ = 60mmHg

The vapor pressure under the second set of conditions is:

$P^{b}$ = 755mmHg - (577mmHg = 222mmHg)

$P^{b}$ = 400mmHg

First question say we should find ΔH(slope) and B(intercept) in the Clausius- Clapeyron equation:

Using the Formula :

$In_p^{0} = \frac{- (delta) H}{RT} + B$

where (delta) H = ΔH

The slope of the $In_p^{0} = \frac{T_1T_2 In (P_2/P_1)}{T_1-T_2}$

Calculating the slope; we have:

$\frac{- (delta) H}{R} = \frac{T_1T_2 In (P_2/P_1)}{T_1-T_2}$

$\frac{- (delta) H}{R}$ = $\frac{331.5 * 383.2 * In (400/60)}{(331.5-383.2)}$

$\frac{- (delta) H}{R}$ = -4661.4k

$\frac{ (delta) H}{R}$ = 4661.4k

The intercept can be derived from the Clausius-Clayperon Equation by making B the subject of the formula. To calculate the intercept using the first set of condition above; we have:

B = $In_p_{1} + \frac{ (delta) H}{RT}$

B = $In 60 + \frac{4661.4}{331.5}$

B = 18.156

Thus the Clausius-Clayperon equation for chlorobenzene can be expressed as:

In P = $\frac{-4661.4k}{T} + 18.156$

In question (b), the air saturated with chlorobenzeneis 130°C, converting he temperature of 130°C to absolute units of kelvin(k) we have;

T = 130°C + 273.2

T = 403.2k

Calculating the vapor pressure using Clausius-Clapyeron equation: we have;

$In_p_{0}$ = $In_p_{0} = \frac{-4661.4}{403.2} + 18.156$

$In_p_{0}$ = 6.595

$p_{0}$ = $e^{6.595}$

$p_{0}$ = 731.mmHg

The vapor pressure of chlorobenzene is 731.4mmHg

The diagram of the flowchart with the seperate vapor and liquid stream can be found in the attached document below.

Afterwards, both the inlet and outlet conditions contain saturated liquid.

From the flowchart, the vapor pressure of chlorobenzene at the inlet and outlet temperatures are known:

$P_1(130^{0}C)$ = 731.44mmHg

$P_1(58.3^{0}C)$ = 60mmHg

To calculate the percentage of the chlorobenzene originally in the vapor pressure that condenses; we must first calculate the mole fractions of chlorobenzene for the vapor inlet and outlet using Raoult's Law:

$y_1 = \frac{P^0 (T)}{P}$

At inlet conditions, the mole fraction of chlorobenzene is:

$y_1 = \frac{731.44}{101.3}*\frac{101.3}{760}$

$y_1 = \frac{0.962 mol cholorobenzene}{mol saturated air}$

At outlet conditions , the mole fraction of chlorobenzene is:

$y_2 = \frac{60}{101.3}*\frac{101.3}{760}$

$y_2 = \frac{0.0789 mol cholorobenzene}{mol saturated air}$

Since there is no reaction, the total balance around the condensation is :

$n_1 = n_2 + n_3$

Let assume, that 100 moles of liquid chlorobenzene (CB) is condensed, therefore the equation becomes:

$n_1 = n_2$ + 100mol

The chlorobenzene balance using the mole fractions calculated above is :

$\frac{0.962mol CB}{mol(air)} * n_1 mol(air) = \frac{0.0789molCB}{mol(air)}*n_2mol(air) + 100CB$

substituting equation (1) into equation above; we have:

$\frac{0.962mol CB}{mol(air)} * n_1 mol(air) = \frac{0.0789molCB}{mol(air)}*(n_2-100)mol(air) + 100CB$

$0.962_n_1 mol = 0.0789_n_1mol + 100mol$

we can solve for n1, i.e ;

n1 = 104.3mol total air

Therefore the moles of chlorobenzene that will produce 100 moles of CB liquid is:

$n_C_B = 104.3 (moles) air * \frac{0.962 mol (CB)}{mol air}$

$n_C_B$ = 100.34mol CB

Now, calculating the percentage of chlorobenzene that condenses: we have;

% CB Condensation = $\frac{100mol}{100.34mol}*100%$

% CB Condensation = 99.7%

The percentage of chlorobenzene originally in the vapor that condenses is 99.7%

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4 0

4 years ago

What is the earth’s convention currents responsible for?

netineya [11]

Convection currents in the magma drive plate tectonics. Heat generated from the radioactive decay of elements deep in the interior of the Earth creates magma (molten rock) in the aesthenosphere. Theaesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the Earth that extends to 2900 km.

4 0

4 years ago

Which of the following is not a diatomic molecule? nitrogen hydrogen bromine helium

Nikitich [7]

Answer: Option (d) is the correct answer.

Explanation:

When two atoms are bonded together then it is known as a diatomic molecule.

Such as nitrogen exists as $N_{2}$ molecule in atmosphere so, it is a diatomic molecule.

Hydrogen also exists as $H_{2}$ molecule in atmosphere so, it is also a diatomic molecule. Also, bromine is a diatomic molecule because it exists as $Br_{2}$ molecule into the atmosphere.

But helium exists as He molecule as it has 2 electrons so, as per the octet rule it's s-shell is completely filled. Hence, it is stable and exists as a monoatomic molecule into the atmosphere.

Thus, we can conclude that out of the given options, helium is not a diatomic molecule.

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3 years ago

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A student is studying the process of weathering and erosion by wind. The student takes down notes shown below:

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Answer:

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