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3 years ago

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Consider the reaction: 2 HCl(aq) + Ba(OH)2(aq) BaCl2(aq) + 2 H2O(l); H = –118 kJ. Calculate the change in temperature when 50.

0 mL of 0.20 M HCl(aq) and 50.0 mL of 0.10 M Ba(OH)2(aq) are mixed together. The density ofthe solution is 1.00 g/mL and Solution= 4.184 J/g-°C

1 answer:

Alborosie3 years ago

6 0

Answer:

ΔT = 1,41°C

Explanation:

For the reaction:

2HCl(aq) + Ba(OH)₂(aq) → BaCl₂(aq) + 2 H₂O(l); ΔH = –118 kJ.

If moles of reaction are:

HCl:

0,0500L×0,20M = 0,01moles

Ba(OH)₂:

0,0500L×0,10M = 0,005moles

The heat produced is:

0,005mol×-118 kJ/mol = -0,59 kJ = -590 J

The temperature increasing is:

Q = -C×m×ΔT

Where Q is heat (-590 J), m is mass of solution (100mL = 100g -density of 1,00g/mL) and ΔT is change in temperature.

Replacing:

-590J = -4,184J/g°C×100g×ΔT

<em>ΔT = 1,41°C</em>

<em></em>

I hope it helps!

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how many grams of potassium chloride, KCL(molar mass is 74.55g/mol) are produced if 25 grams of potassium chlorate KClo^3 decomp

JulsSmile [24]

Answer:

Mass = 15.20 g of KCl

Explanation:

The balance chemical equation for the decomposition of KClO₃ is as follow;

2 KClO₃ = 2 KCl + 3 O₂

Step 1: Calculate moles of KClO₃ as;

Moles = Mass / M/Mass

Moles = 25.0 g / 122.55 g/mol

Moles = 0.204 moles

Step 2: Find moles of KCl as;

According to equation,

2 moles of KClO₃ produces = 2 moles of KCl

So,

0.204 moles of KClO₃ will produce = X moles of KCl

Solving for X,

X = 2 mol × 0.204 mol / 2 mol

X = 0.204 mol of KCl

Step 3: Calculate mass of KCl as,

Mass = Moles × M.Mass

Mass = 0.204 mol × 74.55 g/mol

Mass = 15.20 g of KCl

6 0

3 years ago

A 0.580 g sample of a compound containing only carbon and hydrogen contains 0.480 g of carbon and 0.100 g of hydrogen. At STP, 3

Sati [7]

Answer:

Molecular formula for the gas is: C₄H₁₀

Explanation:

Let's propose the Ideal Gases Law to determine the moles of gas, that contains 0.087 g

At STP → 1 atm and 273.15K

1 atm . 0.0336 L = n . 0.082 . 273.15 K

n = (1 atm . 0.0336 L) / (0.082 . 273.15 K)

n = 1.500 × 10⁻³ moles

Molar mass of gas = 0.087 g / 1.500 × 10⁻³ moles = 58 g/m

Now we propose rules of three:

If 0.580 g of gas has ____ 0.480 g of C _____ 0.100 g of C

58 g of gas (1mol) would have:

(58 g . 0.480) / 0.580 = 48 g of C

(58 g . 0.100) / 0.580 = 10 g of H

48 g of C / 12 g/mol = 4 mol

10 g of H / 1g/mol = 10 moles

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3 years ago

Omg GUYS I NEED HELPPP

Ilia_Sergeevich [38]

27) Partial pressure of oxygen: 57.8 kPa

29) Final volume: 80 mL

30) Final volume: 8987 L

31) Due to property of water of being polar, ice floats on water

Explanation:

27)

In a mixture of gases, the total pressure of the mixture is the sum of the partial pressures:

$p_T = p_1 + p_2 + ... + p_N$

In this problem, the mixture contains 3 gases (helium, carbon dioxide and oxygen). We know that the total pressure is

$p_T=201.4 kPa$

We also know the partial pressures of helium and carbon dioxide:

$P_{He}=125.4 kPa\\P_{CO_2}=18.2 kPa$

The total pressure can be written as

$p_T=p_{He}+p_{CO_2}+p_{O_2}$

where $p_{O_2}$ is the partial pressure of oxygen. Therefore, we find

$p_{O_2}=p_T-p_{He}-p_{CO_2}=201.4-125.4-18.2=57.8 kPa$

29)

Assuming that the pressure of the gas is constant, we can apply Charle's law, which states that:

"For an ideal gas at constant pressure, the volume of the gas is proportional to its absolute temperature"

Mathematically,

$\frac{V}{T}=const.$

where

V is the volume of the gas

T is the Kelvin temperature

We can re-write it as

$\frac{V_1}{T_1}=\frac{V_2}{T_2}$

Here we have:

$V_1 = 42 mL$ (initial volume)

$T_1=-89^{\circ}C+273=184 K$ is the initial temperature

$T_2=77^{\circ}C+273=350 K$ is the final temperature

Solving for V2, we find the final volume:

$V_2=\frac{V_1 T_2}{T_1}=\frac{(42)(350)}{184}=80 mL$

30)

For this problem, we can use the equation of state for ideal gases, which can be written as

$\frac{p_1 V_1}{T_1}=\frac{p_2 V_2}{T_2}$

where in this problem:

$p_1 = 102.3 kPa$ is the initial pressure

$V_1=1975 L$ is the initial volume

$T_1=25^{\circ}C+273=298 K$ is the initial temperature

$p_2=21.5 kPa$ is the final pressure

$T_2=12^{\circ}C+273=285 K$ is the final temperature

And solving for V2, we find the final volume of the balloon:

$V_2=\frac{p_1 V_1 T_2}{p_2 T_1}=\frac{(102.3)(1975)(285)}{(21.5)(298)}=8987 L$

31)

A molecule of water consists of two atoms hydrogen bond with an atom of oxygen ( $H_2 O$ ) in a covalent bond.

While the molecul of water is overall neutral, due to the higher electronegativity of the oxygen atom, electrons are slightly shifted towards the oxygen atom; as a result, there is a slightly positive charge on the hydrogen side, and a slightly negative charge on the oxygen side (so, the molecules is said to be polar).

As a consequence, molecules of water attract each other, forming the so-called "hydrogen bonds".

One direct consequence of the polarity of water is that ice floats on liquid water.

Normally, for every substance on Earth, the solid state is more dense than the liquid state. However, this is not true for water, because ice is less dense than liquid water.

This is due to the polarity of water. In fact, when the temperature of water is decreased to freezing point and water becomes ice, the hydrogen bondings "force" the molecules to arrange in a lattice structure, so that the molecules become more spaced when they turn into solid state. As a result, ice occupies more volume than water, and therefore it is less dense, being able to float on water.

Learn more about ideal gases:

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3 years ago

A liquid is placed in an evacuated, sealed flask. When will this closed system reach dynamic equilibrium?

timurjin [86]

The liquid will stop converting into vapor. This process is to balanced the amount of substance of both phases inside the flask.

4 0

3 years ago

Read 2 more answers

A car traveling at a constant speed travels 175 miles in four hours. How many minutes will it take for the car to travel 1000 fe

elena-14-01-66 [18.8K]

It takes 0.26 minutes to travel 1000 feet

<u>Solution:</u>

Given that car traveling at a constant speed travels 175 miles in four hours

Distance = 175 miles

Time taken = 4 hours

Convert the units to feet and minute

Given that,

1 mile = 5280 feet

175 miles = 5280 x 175 feet = 918720 feet

Also we know that,

1 hour = 60 minutes

4 hours = 60 x 4 minutes = 240 minutes

Thus, we got,

Distance = 918720 feet

Time taken = 240 minutes

<em><u>Find the speed of car</u></em>

<em><u>Speed is given by formula:</u></em>

$speed = \frac{distance}{time}$

$speed = \frac{918720}{240} = 3828$

Thus speed of car is 3828 feet per minute

<em><u>How many minutes will it take for the car to travel 1000 feet?</u></em>

Let "x" be the minutes needed for 1000 feet

speed of car is 3828 feet per minute

1 minute = 3828 feet

x minute = 1000 feet

This forms a proportion. We can solve by cross multiplying

$x \times 3828 = 1000 \times 1\\\\x = \frac{1000}{3828}\\\\x = 0.26$

Thus it takes 0.26 minutes to travel 1000 feet

7 0

3 years ago