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dimulka [17.4K]

3 years ago

15

In a problem, you are given two pressures and one temperature at constant volume and amount of gas. You are asked to find a seco

nd temperature. What law should you use?

2 answers:

Andrew [12]3 years ago

8 0

Answer:

Gay-Lussac's Law.

Step-by-step explanation:

The volume and number of moles are constant, so we can use <em>Gay-Lussac’s Law</em>:

At constant volume, the pressure exerted by a gas is directly proportional to its temperature.

p₁/T₁ = p₂/T₂ Invert each side of the equation

T₁/p₁ = T₂/p₂ Multiply each side by p₂

T₂ = T₁ × p₁/p₂

p₂ = p₁ × T₂/T₁

The units for the pressures don't matter if you use <em>same units for each pressure</em>.

However, the temperatures must be <em>absolute values</em>, usually measured in kelvins.

laiz [17]3 years ago

3 0

I don't know who it was named for but the law is

P1/T1 = P2/T2

Make sure the pressure units are the same (atmospheres or kPa usually) and that the temperature is in Degrees Kelvin which is derived from Celsius degrees.

Try Charles' Law for the name.

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Oxana [17]

Answer:

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Explanation:

4 0

3 years ago

Read 2 more answers

3. After 7.9 grams of sodium are dropped into a bathtub full of water, how many grams of hydrogen gas are released?

Pavel [41]

Answer:

3) About 0.35 grams of hydrogen gas.

4) About 65.2 grams of aluminum oxide.

Explanation:

Question 3)

We are given that 7.9 grams of sodium is dropped into a bathtub of water, and we want to determine how many grams of hydrogen gas is released.

Since sodium is higher than hydrogen on the activity series, sodium will replace hydrogen in a single-replacement reaction for sodium oxide. Hence, our equation is:

$\displaystyle \text{Na} + \text{H$_2$O}\rightarrow \text{Na$_2$O}+\text{H$_2$}$

To balance it, we can simply add another sodium atom on the left. Hence:

$\displaystyle 2\text{Na} + \text{H$_2$O}\rightarrow \text{Na$_2$O}+\text{H$_2$}$

To convert from grams of sodium to grams of hydrogen gas, we can convert from sodium to moles of sodium, use the mole ratios to find moles in hydrogen gas, and then use hydrogen's molar mass to find its amount in grams.

The molar mass of sodium is 22.990 g/mol. Hence:

$\displaystyle \frac{1\text{ mol Na}}{22.990 \text{ g Na}}$

From the chemical equation, we can see that two moles of sodium produce one mole of hydrogen gas. Hence:

$\displaystyle \frac{1\text{ mol H$_2$}}{2\text{ mol Na}}$

And the molar mass of hydrogen gas is 2.016 g/mol. Hence:

$\displaystyle \frac{2.016\text{ g H$_2$}}{1\text{ mol H$_2$}}$

Given the initial value and the above ratios, this yields:

$\displaystyle 7.9\text{ g Na}\cdot \displaystyle \frac{1\text{ mol Na}}{22.990 \text{ g Na}}\cdot \displaystyle \frac{1\text{ mol H$_2$}}{2\text{ mol Na}}\cdot \displaystyle \frac{2.016\text{ g H$_2$}}{1\text{ mol H$_2$}}$

Cancel like units:

$=\displaystyle 7.9\cdot \displaystyle \frac{1}{22.990}\cdot \displaystyle \frac{1}{2}\cdot \displaystyle \frac{2.016\text{ g H$_2$}}{1}$

Multiply. Hence:

$=0.3463...\text{ g H$_2$}$

Since we should have two significant values:

$=0.35\text{ g H$_2$}$

So, about 0.35 grams of hydrogen gas will be released.

Question 4)

Excess oxygen gas is added to 34.5 grams of aluminum and produces aluminum oxide. Hence, our chemical equation is:

$\displaystyle \text{O$_2$} + \text{Al} \rightarrow \text{Al$_2$O$_3$}$

To balance this, we can place a three in front of the oxygen, four in front of aluminum, and two in front of aluminum oxide. Hence:

$\displaystyle3\text{O$_2$} + 4\text{Al} \rightarrow 2\text{Al$_2$O$_3$}$

To convert from grams of aluminum to grams of aluminum oxide, we can convert aluminum to moles, use the mole ratios to find the moles of aluminum oxide, and then use its molar mass to determine the amount of grams.

The molar mass of aluminum is 26.982 g/mol. Thus:

$\displaystyle \frac{1\text{ mol Al}}{26.982 \text{ g Al}}$

According to the equation, four moles of aluminum produces two moles of aluminum oxide. Hence:

$\displaystyle \frac{2\text{ mol Al$_2$O$_3$}}{4\text{ mol Al}}$

And the molar mass of aluminum oxide is 101.961 g/mol. Hence: $\displaystyle \frac{101.961\text{ g Al$_2$O$_3$}}{1\text{ mol Al$_2$O$_3$}}$

Using the given value and the above ratios, we acquire:

$\displaystyle 34.5\text{ g Al}\cdot \displaystyle \frac{1\text{ mol Al}}{26.982 \text{ g Al}}\cdot \displaystyle \frac{2\text{ mol Al$_2$O$_3$}}{4\text{ mol Al}}\cdot \displaystyle \frac{101.961\text{ g Al$_2$O$_3$}}{1\text{ mol Al$_2$O$_3$}}$

Cancel like units:

$\displaystyle= \displaystyle 34.5\cdot \displaystyle \frac{1}{26.982}\cdot \displaystyle \frac{2}{4}\cdot \displaystyle \frac{101.961\text{ g Al$_2$O$_3$}}{1}$

Multiply:

$\displaystyle = 65.1852... \text{ g Al$_2$O$_3$}$

Since the resulting value should have three significant figures:

$\displaystyle = 65.2 \text{ g Al$_2$O$_3$}$

So, approximately 65.2 grams of aluminum oxide is produced.

5 0

3 years ago

Read 2 more answers

Measurements show that unknown x compound has the following composition:

Fudgin [204]

The empirical formula of the compound with the percent composition C 18.1%, H 2.27%, Cl 79.8% is C₂H₃Cl₃.

<h3>What is an empirical formula?</h3>

It is the minimum ratio between the elements that form a compound.

Step 1: Divide each percentage by the molar mass of the element.

C: 18.1/12.01 = 1.51

H: 2.27/1.01 = 2.25

Cl: 79.8/35.45 = 2.25

Step 2: Divide all the numbers by the smallest one.

C; 1.51/1.51 = 1

H: 2.25/1.51 ≈ 1.5

Cl: 2.25/1.51 ≈ 1.5

Step 3: Multiply all the numbers by 2 so all of them are whole.

C: 1 × 2 = 2

H: 1.5 × 2 = 3

Cl: 1.5 × 2 = 3

The empirical formula is C₂H₃Cl₃.

The empirical formula of the compound with the percent composition C 18.1%, H 2.27%, Cl 79.8% is C₂H₃Cl₃.

Learn more about empirical formula here: brainly.com/question/1603500

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7 0

2 years ago

svetoff [14.1K]

Answer:

Semiconductors are poor conductors at low temperatures, but their resistance decreases with increasing temperature.

Explanation:

A semiconductor can be defined as a crystalline solid substance that has its conductivity lying between that of a metal and an insulator, due to the effects of temperature or an addition of an impurity. Semiconductors are classified into two main categories;

1. Extrinsic semiconductor.

2. Intrinsic semiconductor.

The statement which best describes the electrical conductivity of metals and semiconductors is that semiconductors are poor conductors at low temperatures, but their resistance decreases with increasing temperature.

This ultimately implies that, semiconductors are typically an insulator (poor conductor) at low temperatures and a good conductor at high temperatures.

Additionally, conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When the conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.

6 0

2 years ago

Which is the most accurate description of compounds?

baherus [9]

Answer: c.They have a unique set of properties that can be used as identifiers.

Explanation:

Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.

Compounds can be decomposed into simpler constituents using chemical reactions.

Example: Water $(H_2O)$

$2H_2O\rightarrow 2H_2+O_2$

Compounds have different properties than the elements it is made up of.

Thus the most accurate description of compounds is that they have a unique set of properties that can be used as identifiers.

3 0

3 years ago