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3 years ago

What is the air speed of a unladen swallow?

Chemistry

1 answer:

Firdavs [7]3 years ago

3 0

Answer: An african or a european swallow?

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Ethanol (C2H5OH) melts a - 144 oC and boils at 78 °C. The enthalpy of fusion of ethanol is 5.02 kj/mol, and its enthalpy of vapo

hammer [34]

<u>Answer:</u>

<u>For a:</u> The total heat required is 36621.5 J

<u>For b:</u> The total heat required is 58944.5 J

<u>Explanation:</u>

<u>For a:</u>

To calculate the heat required at different temperature, we use the equation:

$q=mc\Delta T$ .........(1)

where,

q = heat absorbed

m = mass of substance

$c$ = specific heat capacity of substance

$\Delta T$ = change in temperature

To calculate the amount of heat required at same temperature, we use the equation:

$q=m\times \Delta H$ ........(2)

where,

q = heat absorbed

m = mass of substance

$\Delta H$ = enthalpy of the reaction

The processes involved in the given problem are:

$1.)C_2H_5OH(l)(35^oC)\rightarrow C_2H_5OH(l)(78^oC)\\2.)C_2H_5OH(l)(78^oC)\rightarrow C_2H_5OH(g)(78^oC)$

<u>For process 1:</u>

We are given:

Change in temperature remains the same.

$m=42.0g\\c_l=2.3J/g.K\\T_2=78^oC\\T_1=35^oC\\\Delta T=[T_2-T_1]=[78-35]^oC=43^oC=43K$

Putting values in equation 1, we get:

$q_1=42.0g\times 2.3J/g.K\times 43K\\\\q_1=4153.8J$

<u>For process 2:</u>

We are given:

Conversion factor: 1 kJ = 1000 J

Molar mass of ethanol = 46 g/mol

$m=42.0g\\\Delta H_{vap}=38.56kJ/mol=\frac{35.56kJ}{1mol}\times (\frac{1000J}{1kJ})\times (\frac{1}{46g/mol})=773.04J/g$

Putting values in equation 2, we get:

$q_2=42.0g\times 773.04J/g\\\\q_2=32467.7J$

Total heat required = $[q_1+q_2]$

Total heat required = $[4153.8J+32467.7J]=36621.5J$

Hence, the total heat required is 36621.5 J

<u>For b:</u>

The processes involved in the given problem are:

$1.)C_2H_5OH(s)(-155^oC)\rightarrow C_2H_5OH(s)(-144^oC)\\2.)C_2H_5OH(s)(-144^oC)\rightarrow C_2H_5OH(l)(-144^oC)\\3.)C_2H_5OH(l)(-144^oC)\rightarrow C_2H_5OH(l)(78^oC)\\4.)C_2H_5OH(l)(78^oC)\rightarrow C_2H_5OH(g)(78^oC)$

<u>For process 1:</u>

We are given:

Change in temperature remains the same.

$m=42.0g\\c_s=0.97J/g.K\\T_2=-144^oC\\T_1=-155^oC\\\Delta T=[T_2-T_1]=[-144-(-155)]^oC=11^oC=11K$

Putting values in equation 1, we get:

$q_1=42.0g\times 0.97J/g.K\times 11K\\\\q_1=448.14J$

<u>For process 2:</u>

We are given:

$m=42.0g\\\Delta H_{fusion}=5.02kJ/mol=\frac{5.02kJ}{1mol}\times (\frac{1000J}{1kJ})\times (\frac{1}{46g/mol})=109.13J/g$

Putting values in equation 2, we get:

$q_2=42.0g\times 109.13J/g\\\\q_2=4583.5J$

<u>For process 3:</u>

We are given:

Change in temperature remains the same.

$m=42.0g\\c_l=2.3J/g.K\\T_2=78^oC\\T_1=-144^oC\\\Delta T=[T_2-T_1]=[78-(-144)]^oC=222^oC=222K$

Putting values in equation 1, we get:

$q_3=42.0g\times 2.3J/g.K\times 222K\\\\q_3=21445.2J$

<u>For process 4:</u>

We are given:

$m=42.0g\\\Delta H_{vap}=38.56kJ/mol=\frac{38.56kJ}{1mol}\times (\frac{1000J}{1kJ})\times (\frac{1}{46g/mol})=773.04J/g$

Putting values in equation 2, we get:

$q_4=42.0g\times 773.04J/g\\\\q_4=32467.7J$

Total heat required = $[q_1+q_2+q_3+q_4]$

Total heat required = $[448.14+4583.5+21445.2+32467.7]J=58944.5J$

Hence, the total heat required is 58944.5 J

8 0

3 years ago

Write the Formulas for these ionic compounds:

Alinara [238K]

Answer:

<h2>1. Tin(IV) oxide</h2>

Tin(IV) oxide, also known as stannic oxide, is the inorganic compound with the formula SnO₂. The mineral form of SnO₂ is called cassiterite, and this is the main ore of tin. With many other names, this oxide of tin is an important material in tin chemistry. It is a colourless, diamagnetic, amphoteric solid.

Formula: SnO₂

Molar mass: 150.71 g/mol

Melting point: 1,630 °C

Density: 6.95 g/cm³

<h2>2. Aluminum oxide</h2>

Aluminium oxide is a chemical compound of aluminium and oxygen with the chemical formula Al₂O₃. It is the most commonly occurring of several aluminium oxides, and specifically identified as aluminium(III) oxide.

Formula: Al₂O₃

Molar mass: 101.96 g/mol

Melting point: 2,072 °C

Density: 3.95 g/cm³

Boiling point: 2,977 °C

ChemSpider ID: 14086

ChemSpider ID: 26988

<h2>3. Silver sulfide</h2>

Silver sulfide is an inorganic compound with the formula Ag ₂S. A dense black solid, it is the only sulfide of silver. It is useful as a photosensitizer in photography. It constitutes the tarnish that forms over time on silverware and other silver objects.

Formula: Ag2S

Molar mass: 247.8 g/mol

Density: 7.23 g/cm³

ChemSpider ID: 145878

<h2>4. Copper (II) sulfate</h2>

Copper(II) sulfate, also known as copper sulphate, are the inorganic compounds with the chemical formula CuSO₄ₓ, where x can range from 0 to 5. The pentahydrate is the most common form. Older names for this compound include blue vitriol, bluestone, vitriol of copper, and Roman vitriol.

Formula: CuSO4

IUPAC ID: Copper(II) sulfate

Molar mass: 159.609 g/mol

Density: 3.6 g/cm³

Melting point: 110 °C

Soluble in: Water

<h2>5. Potassium carbonate</h2>

Potassium carbonate is the inorganic compound with the formula K₂CO₃. It is a white salt, which is soluble in water. It is deliquescent, often appearing as a damp or wet solid. Potassium carbonate is mainly used in the production of soap and glass.

Formula: K2CO3

Molar mass: 138.205 g/mol

IUPAC ID: Potassium carbonate

Density: 2.43 g/cm³

Melting point: 891 °C

Soluble in: Water

Explanation:

Hope it is helpful....

4 0

3 years ago

A student runs two experiments with a constant-volume "bomb" calorimeter containing 1500.g of water.

muminat

Answer:

See explaination

Explanation:

Please kindly check attachment for the step by step solution of the given problem

3 0

3 years ago

A first-order reaction is 81omplete in 264s. A. What is the half-life for this reaction? b. How long will it take for the reacti

Arlecino [84]

A first-order reaction is 81omplete in 264s.The half-life for this reaction (i) t 1/2 = =3.465×10 −3 s.to reach 95% Completion = 285 s.

To measure reaction rates, chemists initiate the reaction, measure the concentration of the reactant or product at different times as the reaction progresses,

For a 0-order response, the mathematical expression that may be employed to determine the half of life is: t1/2 = [R]0/2k. For a first-order reaction, the half of-existence is given by: t1/2 = zero.693/ok. For a 2d-order response, the method for the half-life of the response is: 1/okay[R]0

The 1/2-life of a response (t1/2), is the quantity of time needed for a reactant concentration to lower via half of compared to its initial awareness. Its software is used in chemistry and medicine to are expecting the awareness of a substance over time

Half of the lifestyles is the time required for exactly 1/2 of the entities to decay 50%.

Learn more about first order reaction here:-

#SPJ4

5 0

2 years ago

What is the volume of 4.78g of O2 gas at STP?

My name is Ann [436]

Answer:

Explanation:

The trick here is to realize that if you know the volume of a gas at STP, you can use the fact that

mole of any ideal gas occupies

22.7 L

under STP conditions to calculate how many moles of gas you have in your sample.

Under STP conditions:

1 mole of an ideal gas = 22.7 L

−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

In your case, you know that your sample of gas occupies

2.28 L

under STP conditions, which are currently defined as a pressure of

100 kPa

and a temperature of

∘

This means that your sample will contain

2.28

⋅

molar volume of a gas at STP



1 mole gas

22.7

0.10044 moles gas

Now, the molar mass of the gas is the mass of exactly

mole of the gas. In your case, you know that you get

3.78 g

for every

0.10044

moles, which means that you have

mole

⋅

3.78 g

0.10044

moles

37.6 g

Since this is the mass of

mole of gas, you can say that the molar mass of the gas is

molar mass = 37.6 g mol

−

−−−−−−−−−−−−−−−−−−−−−−−

8 0

3 years ago

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