what is the difference between an exothermic and endothermic reaction.

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:

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:

For evaporation you need a warm, preferably humid temperature. The rate of evaporation increases with an increase in temperature. A windy climate is best, as wind helps to remove the evaporated water vapour, and therefore creating a better scope for evaporation to continue. The speed of wind is important for evaporation because the wind pulls in dry air, increasing the rate of evaporation.

Short Answer- Hot and humid temperature, lots of wind speed.

Answer:

Explanation:

1 Evaporation is the phase change of a liquid to a gas. There are three very important requirements for evaporation to take place, 1) available energy, 2) available water, and 3) a vertical moisture gradient. Approximately 600 calories of heat must be added to a gram of water for it to evaporate into the air.

2. Evaporation is the process of a substance in a liquid state changing to a gaseous state due to an increase in temperature and/or pressure. It is a fundamental part of the water cycle and is constantly occurring throughout nature.

3.Water evaporates faster if the temperature is higher, the air is dry, and if there's wind. The same is true outside in the natural environment. Evaporation rates are generally higher in hot, dry and windy climates.

                                thank u

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

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:

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: a)  Sn 2+  

Explanation:A reducing agent is a substance  that can be oxidized when it loses electrons while An oxidizing agent is a substance that is reduced when it gains   electrons.

 Considering  Cu 2+,   Fe 3+, Al 3+, Here,  Cu 2+ can  be reduce to its Copper metal, same for  Al 3+ to Aluminium  metal  and Fe 3+  to Fe 2+ ion  and will not be oxidized further since they are in their most oxidized states. The three ions are acting as only oxidizing agents.

while Sn 2+ can be oxidized to become Sn 4+ and also  be reduced to become Sn metal  acting as a reducing agent and an oxidizing agent.

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.

Answer: Thus the yield of uranium from 2.50 kg [tex]U_3O_8[/tex] is 2.12 kg

Explanation:

According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number [tex](6.023\times 10^{23})[/tex] of particles.

To calculate the number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{molar mass}}[/tex]

moles of [tex]U_3O_8=\frac{2.50\times 1000g}{842g/mol}=2.97mol[/tex]    (1kg=1000g)

As 1 mole of [tex]U_3O_8[/tex] contains = 3 moles of U

2.97 mole of [tex]U_3O_8[/tex] contains = [tex]\frac{3}{1}\times 2.97=8.91moles[/tex] moles of U

Mass of Uranium=[tex]moles\times {\text {Molar mass}}=8.91mol\times 238g/mol=2120g=2.12kg[/tex]  

 ( 1kg=1000g)

Thus the yield of uranium from 2.50 kg [tex]U_3O_8[/tex] is 2.12 kg

Answer:

A

Explanation:

Answer:

a

Explanation:

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:

231.735 g/mol

Explanation:

Answer:

See explanation below

Explanation:

You forgot to put the picture to do so. In this case, I manage to find one, and I hope is the one you are looking for. If not, then post it again and I'll gladly help you out again.

According to the picture with the answer, we have a cyclohexane with 4 methyl groups there. Two of them are facing towards the molecule with a darker bond. This means that the alkyl bromide, should have a bromine in one of the bonds, and in order to produce an E2 reaction, this bromine should be facing in the opposite direction of the methyl groups which are facing towards. This is because an E2 reaction occurs with the less steric hindrance in the molecule. If the bromine is in the same direction as the methyl group, it will cause a lot more of work to do a reaction, and therefore, an E2 reaction. I will promote instead a E1 or a sustitution product.

Therefore the alkyl bromide should be like the one in the picture 2.

Answer:

342.14g/mol.

Explanation:

The molar mass of Al2 (SO4)3 is 342.15g/mole.

Reasons that one aluminum atom=26.98. Therefore two aluminum atoms:=2(26.98 g/mole) =53.96 g/mole.

Mass of SO4=96.06g/mol.

Therefore molar mass of Al2(SO4)3= 53.96+(96.06)×3=342.14g/mol

Answer:

342.17 g/mol

Explanation:

Al= 26.98    

S= 32.07

O= 16.00

To calculate that you would have

2(26.98) since there are two Als

and then you have to distribute the 3 to the S and O so...

3S and 12O

which is

3(32.07) + 12(16.00)

which means you add

2(26.98) + 3(32.07) + 12(16.00)

=53.96 + 96.21 + 192

=342.17

there you Go! the final answer is 342.17 g/mol.

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:

your answer will be photosynthesis

Explanation:

Answer:

Industrial activity increases the emission of greenhouse gases in the atmosphere, especially carbon dioxide (CO2), and it negatively affects climate by increasing global warming.

Two actions to face the global warming:

1- To substitute the use of fossil fuels by alternative clean energy sources such as, for example, hydroelectric, geothermal, solar and wind energy resources.  

2- The government's policies decided to develop electric cars and to stimulate healthy habits such as walking instead of the use of conventional fossil-fueled transport modes.

Answer:

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

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:

D

Explanation:

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

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:

El reactivo en exceso es hidrógeno

97.12g NH₃ son formados

Explanation:

Basados en la reacción:

N₂(g) + 3 H₂(g) → 2 NH₃(g)

El hidrógeno pasa de estado de oxidación 0 a estado de oxidación +1. Al perder un electrón se oxida y es el agente reductor.

El nitrógeno pasa de estado 0 estado -3. Al ganar 3 electrones se reduce y es el agente oxidante.

100g de N₂ son (Peso molecular: 28g/mol):

100g × (1mol / 28g) = 3.57 moles de N₂

Y 25g de H₂ son (Peso molecular: 2g/mol):

25g × (1mol / 2g) = 12.5 moles de H₂

Como 3 moles de hidrógeno reaccionan por mol de nitrógeno, las moles de nitrógeno que se necesitan para hacer reaccionar completamente 12.5 moles de hidrógeno son:

12.5 moles H₂× (1 mol N₂ / 3 moles H₂) = 4.17 moles de nitrógeno.

Como hay 3.57 moles de nitrógeno, el reactivo en exceso es hidrógeno.

Como el reactivo limitante es el nitrógeno y 1 mol de nitrógeno produce 2 moles de amoniaco, las moles de amoniaco son:

3.57 moles de N₂ × (2 moles NH₃ / 1 mol N₂) = 7.14 moles de NH₃

La masa producida idealmente es:

7.14 mol NH₃ ₓ (17g/mol) = 121.4 g de NH₃. Como la eficiencia del proceso es del 80%:

121.4 g NH₃ × 80% = 97.12g NH₃ son formados

Answer:

Excess reactant: H₂

Mass of produced ammonia,  97.1 g

Explanation:

Identify the reaction:

N₂ + 3H₂  → 2NH₃

We identify the reducing agent and the  oxidizing agent:

N₂ changed the oxidation state from 0 to -3. This is the reduction, so it is the  oxidizing agent. By the way the H₂ is the reducing agent.

We convert the mass to moles:

100 g / 28 g/mol = 3.57 moles of N₂

25 g / 2 g/mol = 12.5 moles of H₂

Ratio is 1:3. For 1 mol of nitrogen, we need 3 moles of hydrogen

Then, 3.57 moles of N₂ would need (3.57 . 3) / 1 = 10.7 moles

We have 12.5 moles of H₂, so the hydrogen is the excess reactant and the nitrogen is the limiting.

To produce ammonia, the reaction needs 1 mol of N₂, that can produce 2 moles of product

3.57 moles of N₂ will produce (3.57 . 2) / 1 = 7.14 moles of NH₃

As yield reaction is 80%, we will produce 7.14 mol . 0.80 = 5.71 moles

We convert the moles to mass: 5.71 mol . 17 g / 1mol = 97.1 g

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

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