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3 years ago

Change in enthalpy when 11.2 dm3 of helium at ntp is heated in a cylinder to 100 degrees celsius

Chemistry

1 answer:

REY [17]3 years ago

8 0

Answer:

Enthalpy change = 333.3 J

Explanation:

Given data:

Volume of helium = 11.2 dm³ or 11.2 L

Temperature = 100 °C (100+273= 373 K)

Enthalpy change = ?

Solution:

Normal temperature of room = 20°C (20+273 = 293 K)

one mole of gas occupy volume = 22.4 L

ΔT = final temperature - initial temperature

ΔT = 373K - 293K

ΔT = 80K

Number of moles of gas = 11.2 L/22.4 l

Number of moles of gas = 0.5 mol

Enthalpy change = nRΔT

Enthalpy change = 0.5 mol × 8.3j/mol.k ×80 K

Enthalpy change = 333.3 J

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What's the possible contaminant in a solution of sodium sulfate and water with the answer being either sodium nitrate, calcium c

Tcecarenko [31]

Answer:

ansser a

Explanation:

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3 years ago

what mass of copper is produce when Zinc is added to a solution containing 31.9g copper (ii) tetraoxosulphate (vi)

Sergio [31]

12.7 grams of copper will be produced.

<h3><u>Explanation</u>:</h3>

Copper is placed below zinc in the metal activity series. This means zinc can replace copper from its salt. Here zinc is added to the salt solution of copper sulphate. The reaction involved is

CuSO4 +Zn =ZnSO4 +Cu.

Zinc sulphate is soluble in the solution and rose red copper will be precipitated from the solution.

From the chemical equation we can see that 1 mole of zinc replaces 1 mole of copper. As no mass of zinc added is mentioned we will assume that excess of zinc is added.

Atomic mass of copper = 63.5

Atomic mass of sulphur = 32.

Atomic mass of oxygen = 16.

So molecular mass of copper sulphate = $63.5 + 32 + 4\times16$ = 159.5.

So, mass of 1 mole of copper sulphate is 159.5 grams.

So, in 31.9 grams of copper sulphate, number of moles of copper sulphate present = $\frac {159.5}{31.9}$ = 0.2

In 1 mole of copper sulphate, 1 mole of copper is present.

So in 0.2 moles of copper sulphate, 0.2 moles of copper is present.

So mass of 0.2 moles of copper = $0.2\times63.5$ = 12.7 grams

8 0

4 years ago

A student finds two unlabeled flasks of clear liquids. One is believed to be 0.1 m nacl and the other to be 0.1 m naclo3. What i

KonstantinChe [14]

Answer:

Add AgNO₃ solution to both unlabeled flasks: based on solubility rules, you can predict that when you add AgNO₃ to the NaCl solution, you will obtain AgCl precipitate, while no precipitate will be formed from the NaClO₃ solution.

Explanation:

<u>1. Adding AgNO₃ to NaCl solution:</u>

AgNO₃ (aq) + NaCl (aq) → AgCl (s) + NaNO₃ (aq)

<u>2. Adding AgNO₃ to NaClO₃ solution</u>

AgNO₃ (aq) + NaClO₃ (aq) → AgClO₃ (aq) + NaNO₃ (aq)

<u />

<u>3. Relevant solubility rules for the problem.</u>

Although most salts containing Cl⁻ are soluble, AgCl is a remarkable exception and is insoluble.

All chlorates are soluble, so AgClO₃ is soluble.

Salts containing nitrate ion (NO₃⁻) are generally soluble and NaNO₃ is not an exception to this rule. In fact, NaNO₃ is very well known to be soluble.

Hence, when you add AgNO₃ to the NaCl solution the AgCl formed will precipitate, and when you add the same salt (AgNO₃) to the AgClO₃ solution both formed salts AgClO₃ and NaNO₃ are soluble.

Then, the precipiate will permit to conclude which flask contains AgCl.

6 0

3 years ago

While boiling potatoes for dinner in salted water, the pot boils over and you notice that the flame on your gas burner turns to

wel

Answer:

This observation can be explained under the following reasons:

High sodium content
Lowered heat temperature
Organic burn

Explanation:

High sodium content from the potato fluid causes the flame to turn yellow, as indicative of the presence of sodium (flame test).

The colour change could also be attributed to the drastic lowering of the burner heat. Finally, pure organics like wood and fats burn red, a would be the case with fluids from the boiled potatoes.

I hope this explanation was helpful.

5 0

3 years ago

What relationship is described by the formula below? (mass of the element/mass of the compound) x 100

Fiesta28 [93]

Introduction
empirical formula
A table of values shows a list of the values for an independent variable, x, matched with the value of the dependent variable, y. In many cases, an equation can be used to relate the two values. If you know the equation, you can easily generate a table of values.

If you are given the table of values, you must determine how the two values are related and then write an equation that shows the relationship.

xy-2-1-100112When looking at the relationship between the y-values and the x-values, it's easy to see that each y-value is 1 more than the x-value. Therefore, the equation that describes this relationship is y = x + 1.

Develop a Rule When Given a Table of Values

Writing an Equation for a Table of Values

Look at the table below. There does not appear to be a constant rate of change.

In this example, we look at the ratio of the change in the pattern of y-values and x-values.

Even though there did not appear to be a constant rate of change, there is actually a constant rate of change of 2.

We're almost ready to write our equation.

We now know the value for m (the slope) in the equation y = mx + b is 2. Since m is 2, we know that each x-value is being multiplied by 2.

What else is happening to the x-value to get the corresponding y-value?

xProcessy-32(-3) + 3-3-12(-1) + 3132(3) + 3962(6) + 31572(7) + 317

We also need to add 3 to the product in order to get the corresponding y-value.

The equation that represents this table of data is y = 2x + 3.

6 0

3 years ago