What is the pH of a 0.640 M solution of C₅H₅NHBr (Kb of C₅H₅N is 1.7 × 10⁻⁹)?

Answer:

4.8 g H₂O

Explanation:

To find the mass of water, you need to (1) convert grams B₂H₆ to moles B₂H₆ (via molar mass from periodic table), then (2) convert moles B₂H₆ to moles H₂O (via mole-to-mole ratio from reaction coefficients), and then (3) convert moles H₂O to grams H₂O (via molar mass from periodic table).

It is important to arrange the ratios/conversions in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 2 sig figs because the given value (3.7 grams) has 2 sig figs.

Molar Mass (B₂H₆): 2(10.811 g/mol) + 6(1.008 g/mol)

Molar Mass (B₂H₆): 27.67 g/mol

1 B₂H₆ + 3 O₂ ---> 2 HBO₂ + 2 H₂O
^                                             ^

Molar Mass (H₂O): 15.998 g/mol + 2(1.008 g/mol)

Molar Mass (H₂O): 18.014 g/mol

3.7 g B₂H₆          1 mole            2 moles H₂O           18.014 g
----------------  x  ---------------  x  -----------------------  x  -----------------  =  4.8 g H₂O
                          27.67 g           1 mole B₂H₆              1 mole

Energy levels inside an atom are the specific energies that electrons can have when energy occupies specific orbitals. Electrons can be excited to higher energy levels by absorbing energy from the surroundings, an equivalent light is emitted when an electron returns from a high energy state to a lower one. Representation of this diagrammatic is known as the energy level diagram.

Answer:

1.20 M (3 s.f.)

Explanation:

In this question, we are trying to find the concentration of KCl after dilution. Note that the number of moles of KCl does not change.

[tex]g \div \frac{g}{mol} = g \times \frac{mol}{g} = mol[/tex]

Number of moles of KCl

= 44.7 ÷74.55

= 0.59960 mol (5 s.f.)

New volume

= 500 mL

= (500 ÷1000) L

= 0.5 L

Concentration after dilution

= 0.59960 ÷0.5

= 1.1992 mol/L

= 1.20 M (3 s.f.)

* M is the symbol for Molarity, which is also equal to mol/L

Answer:

the IUPAC name is: 2-ethyl-3-methyl-pentanal

Answer:

Thus IUPAC name is: 3-methylpentane. Was this answer helpful?

Explanation:

hope it will help you

Aluminum can be oxidized by [tex]Li^{+}[/tex] and [tex]Ca^{2+}[/tex]

Some of the metal corrodes (or oxidizes) and forms the corresponding metal oxide on the surface as a result of a chemical reaction between the metal surface and the oxygen in the air. The corrosion products that occur in some metals, like steel, are highly apparent and loose.

According to reactivity series (The array of metals in the descending order of their reactivities is referred to as the metals' reactivity series. It is sometimes referred to as the metals in the activity series.)

Lithium and calcium ions are more reactive than aluminum ion and they are less electronegative.

Since silver and tin are more electronegative than aluminum so, they cannot oxidize aluminum.

∴ [tex]Li^{+}[/tex] and [tex]Ca^{+2}[/tex] ions can oxidize aluminum.

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There is no delay because the effects of gravity are constantly acting on bodies of water. Hence, option D is correct.

Gravitation or just gravity is the force of attraction between any two bodies.

The Moon exerts over twice the gravitational pull of the Sun on Earth's tides because of its proximity to Earth. -The lunar tidal bulges are about twice the size of the solar tidal bulges. -The Sun's contribution to the tides is less than that of the Moon.

When the sun and moon are perfectly unaligned (they form a 90-degree angle relative to the earth), there are still tides because the moon's gravitational gradient is stronger than the sun's. The sun's gravitational gradient never completely cancels out the moon's.

Hence, option D is correct.

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Gloves is the tool component which will unlikely present a hazard in this scenario.

This is referred to as potential source of harm when performing various types of activities.

Gloves will unlikely cause harm as it is used to prevent the risk of electric shock when handling electrical devices which is why it is the most appropriate choice.

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Answer:

3 ZnS (s) + 2 AIP(s) ---> AI₂S₃(s) +  Zn₃P₂(s)

Explanation:

I believe you are asking for this reaction to be balanced. However, after looking more closely, those are not the products that would be created from the reactants. Assuming this is a double-displacement reaction, and taking the most common charges of the ions into consideration, the actual products would be AI₂S₃(s) + Zn₃P₂(s). I apologize if I assumed incorrectly.

For an equation to be balanced, there needs to be the same amount of each element on both sides of the equation.

The unbalanced equation:

ZnS (s) + AIP(s) ---> AI₂S₃(s) + Zn₃P₂(s)

Reactants: 1 zinc, 1 sulfur, 1 aluminum, 1 phosphorus

Products: 3 zinc, 3 sulfur, 2 aluminum, 2 phosphorus

As you can see, there is an unequal amount of each element on the reactants and products side. To balance the equation, coefficients in front of the compound(s) will be necessary.

The balanced equation:

3 ZnS (s) + 2 AIP(s) ---> AI₂S₃(s) +  Zn₃P₂(s)

Reactants: 3 zinc, 3 sulfur, 2 aluminum, 2 phosphorus

Products: 3 zinc, 3 sulfur, 2 aluminum, 2 phosphorus

Answer:

Verdadero!
no se en que mas quieres que te ayude? o cual realmente quieres que sea la respuesta?

The ionization energy will increase substantially when 11th electron is removed compared to when the 10th electron is removed.

Ionization energy is the energy required to remove one or more electrons from a neutral atom in its gaseous state to form a positively-charged ion.

The ionization energy increases steadily as successive electrons are removed from an atom. A substantial increase in ionization energy occurs with the removal of an electron from a filled inner shell.

The 10th electrons is the last electron in the L shell of atoms. The 11th electron is the first electron in a  filled inner shell.

Therefore, ionization energy will increase substantially when 11th electron is removed compared to when the 10th electron is removed.

Note that there was no attached graph and the answer was given based on the general trend observed in ionization energies.

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Answer:

Sickle cell anemia

Explanation:

is an inherited genetic abnormality of hemoglobin (the oxygen-carrying protein found in red blood cells) characterized by sickle (crescent)-shaped red blood cells and chronic anemia caused by excessive destruction of the abnormal red blood cells.

Answer:

Sickle cell

Explanation:

I just took the test and it was correct.

Gas law refers to the relationship between the temperature, volume and pressure of a gas.

The term gas law refers to the relationship between the temperature, volume and pressure of a gas.

6a) PV =nRT

P = nRT/V

P =  0.898 * 0.082 * 293/24.5

P = 0.88 atm

6b)  Number of  moles of helium = 2.82 g/4 g/mol = 0.705 moles

Pressure =  991 mm Hg or 1.3 atm

V = nRT/P

V = 0.705 * 0.082 * 300/1.3

V = 13.3 L

8a) V = nRT/P

V = 0.814 * 0.082 * 273/1

V = 18.22 L

8b) 1 mole of oxygen occupies 22.4 L

1.21 mole of oxygen occupies   1.21 mole *  22.4 L/ 1 mole

= 27.1 l

9b) C4H10(g) + 13/2O2 -----> 4CO2 + 5H20

1 moles of butane produces 4 moles of CO2, It then follows that the volume of carbon dioxide produced is 4( 7.95 liters) = 31.8 litres

10b) CaCO3 ------> CO2 + CaO

Since the reaction is 1:1,  0.504 mol of CO2 is produced

PV =nRT

V = 0.504 * 0.082 * 273/1 atm

V = 11.3 L

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The percentage of the area under the normal distribution curve would lie above 98.02 on the x-axis is 2.5 % , option C is the answer.

Normal Distribution is a probability distribution which is symmetric about the mean , The frequency is more near the mean and less far from the mean.

It is given in the data that

10,000 more observations were collected

the percentage of the observations would be greater than 98.02 = ?

According to the 68-95-99.7 rule,

It states that approximately

68% of the observations lie within σ of µ

95% of the observations lie within 2σ of µ.

99.7% of the observations lie within 3σ of µ.

The percentage of the observation between various intervals is attached in the image in the answer.

2.1 percent of the population is distributed in the intervals between two and three standard deviations , which is the zone above 2SD and below 3SD.

As 2.1 % is approximate , Therefore from the given option , 2.5%

The percentage of the area under the normal distribution curve would lie above 98.02 on the x-axis is 2.5 % , option C is the answer.

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Answer:

Substance

Explanation:

Any physical matter despite of living or non living things are composed by a set of molecules or atoms commonly known as substance

On specific living things are composed of biomolecules or cells where as non living things are composed of molecules and atoms

Answer:

Substances

Physical matters are divided into 3 states

As per randomness of particles the order is

What is one advantage of wind and hydroelectric power?

A. They are effective in any type of environment.

B. Neither harms wildlife.

C. Neither produces pollutants.

D. Both are inexpensive.

Explanation:

one of the qnswer is flood control, irrigation support, and clean drinking water

The amount of energy absorbed by the 325g of water is 57,057J. Details about calorimetry can be found below.

The energy absorbed by a mass of substance can be calculated using the following formula;

Q = mc∆T

Where;

Q = 325g × 4.18 × (92 - 50)

Q = 57,057J

Therefore, the amount of energy absorbed by the 325g of water is 57,057J.

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The movements of the substance across the dialysis membrane are as following: water: Moves in both directions.

Glucose: Moves into the blood.

Urea: Moves out of the blood.

Na, K, and Ca ions: Moves in both directions.

Dialysis is a process of filtration and purification of blood by a machine. This machine helped those people whose kidney stop working and doesn't purify the blood.

Thus, the correct options are: water: Moves in both directions.

Glucose: Moves into the blood.

Urea: Moves out of the blood.

Na, K, and Ca ions: Moves in both directions.

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Answer:

1 C₂H₆O

Explanation:

The given equation:

C₂H₆O + 3 O₂ ---> 2 CO₂ + 3 H₂O

Reactants: 2 carbon, 6 hydrogen, 7 oxygen

Products: 2 carbon, 6 hydrogen, 7 oxygen

As you can see, the amount of each element on both sides is identical. Therefore, the reaction is already balanced. This means that the coefficient in front of C₂H₆O is 1. When writing the equation, writing the one is insignificant and usually left out.

Answer:

It depends on how high you are above sea level

Explanation:

I did an experiment in my Scince class that showed, the less air that is around water will lessen it’s boiling level. We put water in a glass beaker inside of our vacuum chamber, we made a vacuum in he chamber. Making a vacuum is like being on a mountain, the less air the lower the boiling point. The water then began to boil due to the water evaporating. When we reached to maximum vacuum that we could the water started to boil at 61°C. No the water was not very hot, it was just warm water that just so happened to also be boiling, cool right!!! Anyways, we played with dry ice the next day.

Hoped this helped.

Hope I earned your star rating or helpful rating from this.

the air pressure around the experiment is lower than at sea level

Answer:

c) oil and vinegar

Explanation:

A heterogeneous mixture is a mixture that does not have a "uniform composition" (meaning that the entire mixture is not thoroughly mixed to be the exact same. In different parts of the mixture, there is a              non-consistent / differing composition.)

Oil and vinegar, as you may know, do not thoroughly mix when put together--different parts of the mixture are made of different compositions. Some parts are made of oil, and some are a concentration of vinegar, but because they are not able to be mixed entirely, the mixture is considered a heterogeneous mixture. If you were to take different samples of different parts of the liquid, you would have a clear separation of oil and vinegar.

Milk is thoroughly milk--if you take out a tablespoon, it will be milk entirely--and it will have the same composition as all of the other milk in the bottle.

Air is complicated--and it can be described as either, but the question was likely intending the answer of oil and vinegar.

Vinegar and water do thoroughly mix. Vinegar absorbs water on a molecular level, so the mixture is thoroughly mixed when put together.

(Hope this helps!)

Cr₂O₃ ( s ) + 3H₂S ( g ) → Cr₂S₃ ( s ) + 3H₂O ( l )

mol  Cr₂S₃ = 421 : 200.19 g/mol = 2.103

mol Cr₂O₃ ≈ mol Cr₂S₃ = 2.103 ( equivalent coefficient)

mass Cr₂O₃ = 2.103 x 151.99 g/mol = 319.63 gr

CH3 CH₂OH + 30₂ → 2CO₂ + 3H₂O

Quartz and Feldspar will be comparatively larger in size since they are formed from cooling of magma while Pyroxene and Olivine are formed by the cooling of lava.

Magma is molten rock that is found deep within the earth's crust whereas Lava is molten rocks that comes up and flows on the earth's surface.

Minerals formed from magma and lava have comparatively different sizes.

Minerals formed from magma are larger in size than minerals formed from Lava. This is because minerals formed from magma undergo slower cooling, and thus, have a longer time to grow in size. However, minerals formed from lava have a relatively shorter cooling time and do not grow into very large sizes.

Therefore, Quartz and Feldspar will be comparatively larger in size since they are formed from cooling of magma while Pyroxene and Olivine are formed by the cooling of lava.

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Answer:

A magic number is a number of nucleons (either protons or neutrons, individually) that form complete bands within the atomic nucleus. As a result, atomic nuclei with a magic number of protons or neutrons are significantly more persistent than other nuclei.

The noble gas configurations for

Li= [He] 2s¹, Na=[Ne] 3s¹ and K =[Ar] 4s¹.

Noble gas configurations are the term for the electronic configurations of the atoms for which the electronic configuration becomes very larger i.e, for the higher atomic numbers.

For the noble gas electronic configurations, the noble gas, which is before that atom is written.

So, the Lithium can be represented as [He] 2s¹.

So, the Sodium can be represented as [Ne] 3s¹.

So, the Potassium can be represented as [Ar] 4s¹.

Hence, the noble gas configurations for Lithium= [He] 2s¹, Sodium=[Ne] 3s¹ and potassium =[Ar] 4s¹.

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Answer:

It's a Ionic compound

Explanation:

To tell if CaO (Calcium oxide) is ionic or covalent (also called molecular) we look at the Periodic Table that and see that Ca is a metal and O is a non-metal. When we have a metal and a non-metal the compound is usually considered ionic.

Because we have a metal and non-metal in CaO there will be a difference in electronegativity between the metal and non-metal. This difference results in an electron(s) being transferred from the metal (lower electronegativity) to the non-metal (higher electronegativity). The results in the metal becoming a postitive ion and the non-metal a negative ion. The two opposite charges are attracted and form the ionic bond between atoms in Calcium oxide.

Answer:

An open system is :-

B. A system that allows energy and mass to move in and out of it.

Example :-

Water boiling in a pot on a stove. (Without lid).

Answer:

a chemical compound

HAZMAT Class 6 Toxic and infectious substances.

Answer:

CLASS 2 Gases

Explanation:

Hope this helps