How many moles are there in 500cm3 of a 0.5mol/dm³ solution of sulfuric acid?

Answer:

The percentage yields are as follows :

a) 64.28%

b) 58.03%

c) 69.46%

d) 79.31%

Explanation:

The percentage yield is the ratio of the actual yield of a product to the expected or theoretical yield expressed as a percentage.

Percent yield = actual yield/theoretical yield x 100%

a) from the question, expected yield is 68.3 g whilst the actual yield is 43.9 g

therefore,

Percentage yield = 43.9 g/68.3 g x 100%

                             =  0.64275 x 100%

                             =  64.28%

b) From the question, expected yield is 0.0722 mol while the actual yield is 0.0419 mol. Therefore

Percentage yield = 0.0419 /0.0722 x 100%

                             = 0.58033 x 100%

                             = 58.03%

c) A limiting reactant is the reactant is is completely used in a recation to form a product. That is, it is the reactant that is not in excess.

From the equation of the reaction :

CH3COOH + CH3CH2OH --> CH3COOCH2CH3 + H2O

1 mole of ethanol reacts with 1 mole of acetic acid to give 1 mole of ethyl acetate.

From the question, ethanol is the limiting reactant because it is not in excess. Hence,

4.29 mole of ethanol should produce 4.29 mole of ethyl acetate (expected yield).

However only 2.98 mol of ethyl acetate is produced (actual yield)

Percentage yield = 2.98mol/4.29 mol x 100%

                            =  0.69463 x 100%

                            = 69.46%

d) From the question, acetic acid is in excess hence ethanol is the limiting reactant

therefore from the equation of the reaction:

1 mole of ethanol reacts with 1 mole of acetic acid to give 1 mole of ethyl acetate.

0,58 mol of ethanol should produce 0.58 mol of ethyl acetate (expected yield)

But 0.46 mol of ethyl acetae was produced (actual yield)

Percentage yield = 0.46mol /0.58 mol x 100%

                             = 0.79310 x 100%

                              = 79.31%

Answer:

Test tubes A and B turn a darker blue color.

Explanation:

Based on the information provided in the question it can be said that they should have noticed that Tube A and Tube B turned a dark blue color. This is because the starch turns the solution in the test tubes into a dark blue color due to the negative reaction caused by the conversion of starch present in salivary amylase

Answer:

Some things you could do are recycle more, contribute to organizations that support saving the environment, finding alternate transportation methods such as riding a bike or walking, and finally, you could volunteer.

Answer:

D

Explanation:

Scientists always perform tests and observe and measure in the physical world to prove their points or answer their questions.

Answer:

gold

Explanation:

Answer: The volume of a 0.10 mol/l HCl solution needed to neutralize 10 ml of a 0.15 mol/l LiOH solution is 15 ml

Explanation:

To calculate the volume of acid, we use the equation given by neutralization reaction:

[tex]n_1M_1V_1=n_2M_2V_2[/tex]

where,

[tex]n_1,M_1\text{ and }V_1[/tex] are the n-factor, molarity and volume of acid which is [tex]HCl[/tex]

[tex]n_2,M_2\text{ and }V_2[/tex] are the n-factor, molarity and volume of base which is LiOH.

We are given:

[tex]n_1=1\\M_1=0.10mol/L\\V_1=?mL\\n_2=1\\M_2=0.15mol/L\\V_2=10mL[/tex]

Putting values in above equation, we get:

[tex]1\times 0.10\times V_1=1\times 0.15\times 10\\\\V_1=15mL[/tex]

Thus the volume of a 0.10 mol/l HCl solution needed to neutralize 10 ml of a 0.15 mol/l LiOH solution is 15 ml

Answer:

The answer is 3.87 J/g°C

Explanation:

Here is the equation we are going to use:

[tex]C=\frac{q}{mT}[/tex]

C= specfic heat in J/g°C

q = heat in joules (J)

m = mass in grams (g)

T = change in temperature

Here is what is given:

q = 849 J

m = 95.4 g

T = 48.0 - 25.0 = 23°C

Find:

Specific heat capacity in J/g

The first thing we are going to do is plug everything into the equation:

[tex]C = \frac{849J}{(9.54g)(23degreesC)}[/tex]

Then we are going to solve for C

[tex]C = \frac{849J}{219.42gC} = 3.87 J/gCelsius[/tex]

Hope this helps!

Answer:

The answer is 3.87 J/gC

Answer:

Octane number, measure of the ability of a fuel to resist knocking when ignited in a mixture with air in the cylinder of an internal-combustion engine.

Octane number is also known as octane rating. Octane numbers are based on a scale on which isooctane is 100 (minimal knock) and heptane is 0 (bad knock). The higher the octane number, the more compression required for fuel ignition. Fuels with high octane numbers are used in high performance gasoline engines.

(Hope this helps) Sky

Answer:

The correct option is;

d. Explicit knowledge

Explanation:

Explicit knowledge is the knowledge that can be easily articulated documented stored in a retrieval system accesses, transmitted and shared with others

Tacit knowledge is the skill developed by an individual based on actual experience such that such knowledge comprise of both facts and perspectives

Hence explicit knowledge and tacit knowledge are complementary

The operations performed by Kaia include documentation, storing in a retrieval system (her project report) and accessing what she documented, this is an example of explicit knowledge.

Answer:

Change of color, change in temperature, change of  energy or loss heat, odor etc....

Answer:

your answer will be photosynthesis

Explanation:

Answer:

The answer is A

Explanation:

The earth naturally maintains the heat energy balance by absorbing a sufficient amount of sunlight energy by the terrestrial land and then reverting back the excess sunlight energy back to the space. The increase in abundance of greenhouse gases in the atmosphere results in absorption of sunlight energy which contains infrared photons this is responsible for increasing the global temperature levels hence, responsible for global warming. These infrared photons are reflected to the earth surface instead of sending back to the space. This is responsible for disturbing the heat balance.

Greenhouse gases interact with infrared photons and reflect them back to earth’s surface, hence option A is correct.

The burning of fossil fuels, logging of forests, and raising of livestock all have a rising impact on the climate and temperature of the planet.

This increases the greenhouse effect and causes global warming by adding a significant amount of greenhouse gases to those that are already present in the atmosphere.

The earth naturally maintains the balance of heat energy by receiving enough solar energy through the terrestrial land and then returning any excess energy to space.

Therefore, greenhouse gases such as CO₂ and N₂O interact with infrared photons and reflect them back to earth’s surface.

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A solution is made by mixing 114.g of benzene C6H6 and 83.g of acetyl bromide CH3COBr, the mole fraction of benzene in this solution is 1.45mol.

The term molar mass is defined as the compound is often calculated by adding the quality atomic masses in g/mol of the constituent atoms.

Molar mass of CH3COBr,

Molar Mass = 2 × MM(C) + 3 × MM(H) + 1 × MM(O) + 1 × MM(Br)

= 122.944 g/mol

Molar mass of C6H6,

MM = 6 × MM(C) + 6 × MM(H)

= 6 × 12.01 + 6 × 1.008

= 78.108 g/mol

n(CH3COBr) = mass/molar mass

= 83 /122.944

= 0.675

n(C6H6) = mass/molar mass

= 114 / 78.108

= 1.45

n(CH3COBr),n1 = 0. 675mol

n(C6H6),n2 = 1. 45mol

Thus, the mole fraction of benzene in this solution is 1.45mol.

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Answer: because the phospholipid bilayer formed by these interactions makes a good barrier between the interior and exterior of the cell, because water and other polar or charged substances cannot easily cross the hydrophobic core of the membrane.

Explanation:

A) 4

pH=-log[H+]

pH=-log(10^-4)

B) Weaker

pH of orange juice=4

pH of coffee=5

An acid with pH of 4 is stronger than a pH of 5

C) 7, neither/neutral

pH of water=7

The reason we should store phosphorous in water is because it will ignite on contact with air

Answer:

2.67761514 moles

Explanation:

0.075kg equates to 75g.

This means that the car emits 75g of CO per km.

dividing 75g by the molar mass of CO (28.01g/mol) we get 2.67761514 moles

Energy change is the conversion of the energy stored in reactants to products. In the reaction between hydrogen and iodine, the energy change is -7 kJ/mol. Thus, option D is correct.

Total energy change is the conversion of the energy from a substance to another when the reactant undergoes modification to produce a product.

The reaction is given as,

H₂ + I₂ → 2HI

In the reaction, the bonds between H-H and I-I are broken to release energy that produces two H-I bonds as the product.

Given,

H-H bond = 436 kJ/mol

I-I bond = 151 kJ/mol

H-I bond = 297 kJ/mol

So, 436 kJ/mol + 151 kJ/mol - 2x297 kJ/mol = -7 kJ/mol

Therefore, -7 kJ/mol is the total energy change in the reaction involving hydrogen and iodine.

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Answer: 80

Explanation:

Answer:

Jamal moved his box to storage, but Jude could not move his.

Explanation:

The force they exert needs to be higher than the force of gravity in order for them to move the boxes. Jamal's force is 60N, which is 10N above the force of gravity on the box, which is 50N. However, Jude's force is only 45N and that is lower than 50N, so he won't be able to move the box while Jamal can.

Answer:

A

Explanation:

Answer:

a

Explanation:

Answer:

231.735 g/mol

Explanation:

Answer:

A=yes

B=yes

Explanation:

Just did the same thing

Protons and neutrons are made of quarks but electrons are not. So A is yes, B is Yes and C is No.

Quarks are extremely small substances which join with each other by extremely strong forces and makeup neutrons and protons of the atom. They combine in a similar way that the protons and neutrons combine to form the nucleus of an atom.

Quarks are categorized in flavours and there are 6 different types of flavours of quarks. The flavours differ from each other on the basis of their charge and mass.

The six flavours of quarks are grouped as three pairs. These are up and down, charm and strange and top and bottom.

Quarks are defined as true elementary particles. They have no defined structure and cannot be subdivided into smaller particles.

Therefore, the correct option is A is yes, B is Yes and C is No.

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Answer:

No oxygen

Explanation:

when something is covered in a blanket it prevents the fire from being able to have any oxygen

Answer:

Its called smothering the fire

Explanation:

A fire needs three things to burn always: fuel, oxygen, and a heat source. Eventually the heat source will not be an issue, but the oxygen and fuel is. If the fire is small enough throwing a blanket can quite smother it. What happens is it cuts off the oxygen supply the fire needs long enough for it to die out.

Answer:

whole continents can move.

Answer:

33.5 g/mol

Explanation:

PV=nRT

(1.40 atm)(8.00 L)=n(0.08206)(295 K)

n=0.463 mol

15.50 g/0.463 mol=33.5 g/mol

Answer:

False

Explanation:

Catalysts are reusable because they keep the chemical reactions moving without being consumed.

Answer:

The most important use of liquid crystals is in displays because the molecules of a liquid crystal can control the amount, color, and direction of vibration of the light that passes through them. hope that helps love!

Answer:

They all have the same number of molecules or atoms which is 3.011*10²⁴ molecules or atoms.

5 moles of O = 3.011*10²⁴ molecules or atoms

5 moles of N = 3.011*10²⁴ molecules or atoms

5 moles of MgCl2 = 3.011*10²⁴ molecules or atoms

5 moles of C2H3NO = 3.011*10²⁴ molecules or atoms.

Explanation:

a)

5 moles of O = ?

1 mole of any substance is equal to Avogadro's number which is equal to 6.022×10²³molecules or atoms

From the question above,

5 moles of O = 5 × 6.022*10²³ = 3.011×10²⁴atoms or molecules.

b)

5 moles of N

From the same principle or fundamentally stated fact above,

1 mole of any substance = 6.022*10²³molecules or atom

5 moles of N = 5 × 6.024

2*10²³ = 3.011*10²⁴atoms or molecules.

c)

5 moles of MgCl₂

Same principle we used in a and b,

1 mole of any substance = 6.022*10²³ atoms or molecules

5 moles of MgCl2 = 5.0×6.022*10²³ = 3.011*10²⁴ atoms or molecules.

d)

5 moles of C₂H₃NO = ?

1 mole of C₂H₃NO = 6.022*10²³molecules or atoms

5 moles = x molecules or atoms

x = 5 × 6.024

2*10²³ = 3.011*10²⁴ atoms or molecules

What this proves is that no matter the compound, molecule or element, as long as they have equal amount of moles, they'll have the same number of atoms, molecules or particles.

Answer:

a. 3.011x10²⁴ atoms of O in 5 moles.

b. 3.011x10²⁴ atoms of N in 5 moles.

c. 3.011x10²⁴ atoms of MgCl₂ in 5 moles.

d. 3.011x10²⁴ atoms of C₂H₃NO in 5 moles

Explanation:

A mole is defined as the number of atoms in exactly 12.000g of ¹²C.

This number is equal to 6.022x10²³. That means 1 mole is equal to 6.022x10²³.

Thus:

a. O . 5 moles of oxygen (An atom) are:

5 moles O ₓ (6.022x10²³ atoms of O / mole) = 3.011x10²⁴ atoms of O in 5 moles

b. N . Also, 5 moles of nitrogen are:

5 moles N ₓ (6.022x10²³ atoms of N / mole) = 3.011x10²⁴ atoms of N in 5 moles

c. MgCl₂ . Magnesium chloride is a molecule. Again, 1 mole of MgCl₂ contains 6.022x10²³ molecules and 5 moles are:

5 moles MgCl₂ ₓ (6.022x10²³ molecules of MgCl₂ / mole) = 3.011x10²⁴ atoms of MgCl₂ in 5 moles

d. C₂H₃NO. 5 moles of C₂H₃NO are:

5 moles  C₂H₃NO ₓ (6.022x10²³ molecules of  C₂H₃NO / mole) = 3.011x10²⁴ atoms of C₂H₃NO in 5 moles

As you can see, number of molecules of 1 mole doesn't depend on the nature of the substance.

Answer:

1. 0.56 mole of electron.

2. 0.28 mole of Co .

3. 16.52g of Co.

Explanation:

The following data were obtained from the question:

Current (I) = 15A

Time (t) = 1 hr = 1 x 60 x 60 = 3600secs

Next, we shall determine the quantity of electricity, Q flowing in electrolyte. This is illustrated below:

Quantity of electricity (Q) = current (I) x Time

Q = It

Q = 15 x 3600

Q = 54000C.

1. Determination of the moles of electrons used to electrolyzed the solution. This is illustrated below:

96500C = 1 mole of electron

Therefore, 54000C = 54000/96500 = 0.56 mole of electron.

Therefore, 0.56 mole of electron was used to electrolyze the solution.

2. Determination of the number of mole of Co produced at the cathode. This is illustrated below:

At the cathode:

Co2+ + 2e —> Co

From the balanced equation above,

2 moles of electron produce 1 mole of Co.

Therefore, 0.56 mole of electron will produce = 0.56/2 = 0.28 mole of Co.

Therefore, 0.28 mole of Co is produced at the cathode.

3. Determination of the mass of Co produced at the cathode. This can be achieved by doing the following:

Molar mass of Co = 59g/mol

Number of mole of Co = 0.28 mole

Mass of Co =..?

Mass = mole x molar mass

Mass of Co = 0.28 x 59

Mass of Co = 16.52g

Therefore, 16.52g of Co is produced at the cathode.