In heating and melting curves, what is the name of the heat associated with the solid-liquid phase? A. Heat of formation B. Heat of fusion C. Heat of sublimation D. Heat of vaporization

Answer:

Yes, at 20 °C the tank was filled to full capacity

Explanation:

Given;

let initial pressure, P₁ = 2.37 atm

let initial volume, V₁ = 1860 L

let final pressure, P₂ = 220 bar = 217.123 atm

let final volume, V₂ = ?

Subject the air volume (1860 L )  at 2.37 atm to the tank rating (220 bar)

Ideal law is given by;

PV = nRT

At a fixed mole and gas temperature, the equation becomes;

P₁V₁ = P₂V₂

V₂ = (P₁V₁) / P₂

V₂ = (2.37 x 1860) / 217.123

V₂ = 20.3 L

After subjecting the air volume to tank rating, the volume of the air at 220 bar is 20.3 L which is greater than tank volume (18 L).

The extra 2.3 L can be assumed to be compressed gas volume due to the given (lower) temperature.

Thus, at 20 °C the tank was filled to full capacity.

Answer: the answer is B estimation

Explanation:

i just took a test

The one that is represented by the number of significant figures in a quantity is scientific notation. The correct option is D.

Scientific notation is a method of expressing numbers that are either too large or too small to be written in decimal form.

In the United Kingdom, it is known as scientific form, standard index form, or standard form.

The proper scientific notation format is an x 10b, where an is a number or decimal number with an absolute value greater than or equal to one and less than ten, or 1 |a| 10. b is the power of ten required for scientific notation to be mathematically equivalent to the original number.

Scientific notation is represented by the number of significant figures in a number.

Thus, the correct option is D.

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Answer:

Weight = mass × earth's gravitational acceleration

Explanation:

Follow the following steps to measure the mass and weight of an object:

Answer:

The volume will also decrease.

Explanation:

This illustration clearly indicates Boyle's law.

Boyle's law states that the volume of a fixed mass of gas is directly proportional to the absolute temperature, provided the pressure remains constant. Mathematically, it is represented as:

V & T

V = KT

K = V/T

V1/T1 = V2/T2 =... = Vn/Tn

Where:

T1 and T2 are the initial and final temperature respectively, measured in Kelvin.

V1 and V2 are the initial and final volume of the gas respectively.

From the illustration above, the volume is directly proportional to the temperature. This implies that as the temperature increases, the volume will also increase and as the temperature decreases, the volume also will decrease.

Answer:

D. At different distances from the nucleus

Explanation:

Electrons are found outside the nucleus on electron shells.

These electron shells extend outwards from the nucleus, so the electrons are found at different distances further away from the nucleus if they are on different electron shells.

Answer:

5.31×10¯²³ g.

Explanation:

Data obtained from the question include:

Molar weight of O2 = 32 g/mol

Mass of 1 oxygen atom =..?

From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms.

This implies that 1 mole of O2 also contains 6.02×10²³ atoms.

1 mole of O2 = 32 g

The mass of 1 atom of O2 can be obtained as follow:

32 g of O2 contains 6.02×10²³ atoms.

Therefore Xg of O2 will contain 1 atom i.e

Xg of O2 = 32/6.02×10²³

Xg of O2 = 5.31×10¯²³ g

Therefore, the mass of a single oxygen atom is 5.31×10¯²³ g.

The mass of a single oxygen atom is 5.31 x 10⁻²³ grams. Therefore, option D is correct.

The molecular weight of oxygen gas is 32 g/mol. To find the mass of a single oxygen atom, divide the molecular weight by Avogadro's number (6.022 x 10²³ atoms/mol).

Avogadro's number (6.022 x 10²³) represents the number of particles (atoms, molecules, or ions) in one mole of a substance.

To find the mass of a single oxygen atom, divide the molecular weight of oxygen gas by Avogadro's number:

Mass of a single oxygen atom = (32 g/mol) / (6.022 x 10²³ atoms/mol)

Simplifying the expression:

Mass of a single oxygen atom = 5.31 x 10⁻²³ g

Therefore, the mass of a single oxygen atom is 5.31 x 10⁻²³ grams.

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Answer:

The Kₐ of the weak acid is 1.033×10⁻⁴

Explanation:

The dissociation of a weak acid in aqueous solution is limited to about 5 to 10%

The acid dissociation reaction is given as follows;

HA (aq) + H₂O (l) → H₃O⁺(aq) + A⁻ (aq)

Given that the pH = 2.5, we have

pH = -log₁₀[H₃O⁺] = 2.5

∴ [H₃O⁺] = 10^(-2.5) = 0.0031623

[tex]K_a = \dfrac{[H_3O^+][A^-]}{[HA]}[/tex]

Kₐ = [H₃O⁺][A⁻]/[HA] = (0.0031623^2)/(0.1 - 0.0031623) = 1.033×10⁻⁴

The acid dissociation constant, Kₐ for weak acid is very low as obtained

Answer:

Allison walks 5 blocks west and 3 blocks south.

Explanation:

Vectors have both magnitude and direction. The attached figure shows the graph of Allison’s walk to school. She follows the black vectors to get to her school.

The first vector on the horizontal axis points towards west and there are 5 blocks. Initially, she walks 5 blocks in west direction.

The second vector points in the negative vertical axis. It means that she walks  3 block in south direction.

Hence, the correct option is (D) i.e. Allison walks 5 blocks west and 3 blocks south.

Answer:

Explanation:

Ohm's Law. The relationship between voltage, current, and resistance is described by Ohm's law. This equation, i = v/r, tells us that the current, i, flowing through a circuit is directly proportional to the voltage, v, and inversely proportional to the resistance, r.

Answer:

A. Br

Explanation:

Atomic radius increases down the group. As the increase in the attractive force of the nucleus increases owing to increase in the size of its positive charges, extra electrons are added to the shells to more than counterbalance this effect down the group hence the atomic radius becomes larger. Iodine has a larger atomic radius than bromine.

Secondly, the ionic radius of a negative ion is greater than its corresponding atomic radius since a negative ion is formed by adding a negative charge (electron) to the atom thus making it bigger. Hence the radius of I^- is greater than that of Br^-.

This means that Br atom must possess the smallest radius among the options listed.

Answer:

D

Explanation:

Br-

Answer:

b

Explanation:

Answer:

(b) BeF2 > OF2 > CH3OH

Explanation:

The degree and type of intermolecular forces present in a substance influences its vapour pressure considerably. The greater the magnitude and strength of intermolecular forces in the substance, the lower the vapour pressure of the substance.

BeF2 molecules are held together by weak vanderwaals forces hence BeF2 will exhibit the least degree of intermolecular interaction and have the highest vapour pressure. OF2 molecules are bound together by dipole interactions hence it will exhibit a lower vapour pressure compared to BeF2. CH3OH molecules form hydrogen bonds with water molecules hence it will exhibit the least vapour pressure among the trio.

Answer:

Client's total intake = 32 ounce of liquid meal supplement

Explanation:

Given:

Meal take

8 ounces of pears

8 ounces of ginger

8 ounces of peaches

liquid meal supplement = 8 ounces

Find:

Client's total intake.

Computation:

Client's total intake = 8 ounces of pears + 8 ounces of ginger + 8 ounces of peaches + 8 ounces liquid meal supplement  

Client's total intake = 32 ounce of liquid meal supplement

Answer:  [tex]CH_3CH_2CH_2CHO[/tex] has aldehyde functional group.

Explanation:

Functional groups are specific group of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.

A.  [tex]CH_3CH_2CH_2COCH_3[/tex] has ketone [tex]C=O[/tex] functional group .

B.  [tex]CH_3CH_2CH_2COOH[/tex] has carboxylic acid [tex]COOH[/tex] functional group .

C.  [tex]CH_3CH_2CH_2CHO[/tex] has  aldehyde [tex]H-C=O[/tex] functional group .

D. [tex]CH_3CH_2CH_2COOCH_3[/tex] has ester [tex]RO-C=O[/tex] functional group .

Thus [tex]CH_3CH_2CH_2CHO[/tex] has aldehyde (CHO) group.

Answer:

Molecule

Explanation:

Compounds are chemical substances comprising of two or more elements. The smallest particle contained in a compound is the MOLECULE. Molecules are combinations of atoms (same or different) of an element held together by a chemical bond.

Since a compound is a molecule with two or more elements combined, the chemistry of the molecules contained in a compound determines its chemical properties. This means that the molecules of a compound are responsible for the interactions of a compound in a chemical reaction. Examples of molecules are H2O, N2, O3 etc.

Answer:

HC2H3O2

Explanation:

Acetic acid is a colorless organic compound liquid called ethanoic acid. It has molar mass of 60.052 g/mol. It is soluble in water. Its formula is CH3COOH. If water is combined with HC2H3O2 then it will give rise to acetic acid solution. When acetic acid is combined with water it creates hydronium and acetate ions.

Answer:

18 electrons

Explanation:

Each electron carry a -1 charge.

Since Oxygen atom originally has 16 electrons (same no. as no. of protons, where net charge as 0), it must add 2 electrons to bring the net charge to -2. Hence, the number of electrons in this ion is 16 + 2 = 18.

Answer:

(a) Total impurities = 17.5%

(b)

(i) 5 tons of ore yields 2185 kg of aluminium

(ii) 5 tons of ore contains 375 kg of sand

(c) Percentage of Al2O3 in purified ore = 825/900 = 91.7%

Explanation:

Q7. Aluminum is extracted from the ore bauxite, which is impure aluminum oxide.

1 tonne (1000 kg) of the ore was found to have this composition:

1. aluminum oxide 825 kg  (82.5%)

2.iron(III) oxide 100 kg  (10%)

3.sand 75 kg (7.5%)

(a) Since we are interested only in extracted aluminium, everything other than aluminium oxide is considered impurity, which includes Fe2O3 (10%) and sand (7.5%).  Total impurities = 10+7.5 = 17.5%

(b)  "1 tonne of the ore gives 437 kg of aluminum."

(i) 1 ton of ore : 437 kg Al  = 5 tons of ore : x kg of Al

Cross multiply

x = 5 tons * 437 kg / 1 ton = 2185 kg of aluminium

(ii) 1 ton of ore contains 75 kg of sand

5 tons of or contains x kg

x = 5*75/1 = 375 kg of sand

(c) If the ore is purified from Fe2O3, then for each ton of ore, there will be left

825 kg of aluminium oxide,

75 kg of sand

for a total of 900 kg.

Percentage of Al2O3 = 825/900 = 91.7%

Answer:

A) 17.5 %

B) 1) 2135 kg

2) 375 kg

C) 91.8%

Explanation:

Part (A):

1 tonne = 1000 kg = 100%

Aluminium oxide = 825 kg = 82.5%

Iron (III) oxide = 100 kg = 10%

Sand = 75 kg = 7.5%

That makes total of 100%

So, the percentage of impurities = Iron (III) oxide + Sand

=> 10 + 7.5 = 17.5%

Part (B):

(1) 1 tonne = 427 kg

Multiplying both sides by 5

=> 5 tonne = 427 * 5

=> 5 tonnes = 2135 kg

(2) 1 tonne contains 75 kg sand as impurity

=> 1 tonne = 75 kg

Multiplying both sides by 5

=> 5 tonnes = 75*5

=> 5 tonnes = 375 kg

Part (C):

If all of the iron oxide was removed, then only aluminium and sand are left.

Aluminium = 825 kg

Sand = 74 kg

Total of them makes it:

=> 825 + 74 = 899

So,

%age of Aluminium = [tex]\frac{825}{899} * 100[/tex]

%age of Aluminium = 0.918 * 100%

%age of Aluminium = 91.8%

Answer:

[tex]\boxed{C}[/tex]

Explanation:

The electrons farthest away from the nucleus are the valence electrons of an atom.

The valence electrons are the electrons orbiting in the last shell around the nucleus.

Answer:

Option C

Explanation:

The electrons that are the farthest away from the nucleus are valence electrons. These are electrons are present in the outermost shell which is also called valence shell.

Answer:

Fossil fuels are formed when living organisms die, and are buried under a tick layer of earth materials over a long time, usually over million s of years. Fossil fuels are formed under intense heat and pressure on the dead organisms due to the earth layer that has accumulated on the organisms over the years. The type of fossil fuels formed in a particular region depends on the type of organism that has lived in that region over the years, and the climate of the region. Regions with lush, swamp forests with many trees have enough  organic material to make coal over the years. The United states however still depend on the importation of other fossil fuel that are in minimal quantity in the country. Most regions have coal, because they once had forests and animals on them but countries like the United States and some other countries have them in abundance, because these regions had a huge amount of lush, swamp forests with many trees. Japan lacks significant domestic reserves of fossil fuel, except coal, and must import substantial amounts of crude oil, natural gas, and other energy resources, because of its climate and the fact that it is an island nation.

Fossil fuels are distributed unevenly because their formation requires precise conditions that aren’t found everywhere. For fossil fuels to form, they need to be subjected to anoxic (lacking oxygen) conditions that allow for great pressure, such as those found beneath the ocean floor.nation:

Answer:

D a substance that increases the rate of a reaction without being used up itself in a reaction.

Explanation:

Examples are

ammonia synthesis ==> iron

sulfuric acid manufacture ==> nitrogen(II) oxide, platinum

cracking of petroleum==> zeolites

hydrogenation of unsaturated hydrocarbons ==> nickel, platinum, or palladium

I hope it helps

Answer:

Hey there!

The correct answer would be D. "a substance that increases the rate of a reaction without being used up itself in a reaction."

Hope this helps :)

Answer:

The correct option is;

a. 255.0 g

Explanation:

The given information are;

Mass of propane, C₃H₈ in the combustion reaction = 156.06 g

The equation of the combustion reaction is C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

From the balanced chemical equation of the reaction, we have;

One mole of propane, C₃H₈ reacts with five moles oxygen gas, O₂, to form three moles of carbon dioxide, CO₂, and  four moles of water, H₂O

The molar mass of propane gas = 44.1 g/mol

The number of moles, n, of propane gas = Mass of propane gas/(Molar mass of propane gas) = 156.06/44.1 = 3.54 moles

Given that one mole of propane gas produces 4 moles of water molecule (steam) H₂O, 3.54 moles of propane gas will produce 4×3.54 = 14.16 moles of  (steam) H₂O

The mass of one mole of H₂O = 18.01528 g/mol

The mass of 14.16 moles of H₂O = 14.16 × 18.01528 = 255.0 g

The mass of H₂O produced = 255.0 g

Answer:

The energy needed to split an atom into separate protons, neutrons, and electrons

Explanation:

The equation E = MC^2 is developed by Einstein’s Special Relativity Theory

where,

E = Energy

M = mass

C = speed of the light

The energy should be measured in Joules i.e J

The mass should be measured in Kilogram i.e Kg

And, the speed of the light should be measured in meters per second i.e ms-1

The C should be squared

Now the energy is required to divided into three particles i.e protons, electrons and neutrons

It also needs to allocate the nucleus into distinct protons and neutrons that we called binding energy of nuclear

And if the energy is required to take off an electron from an atom we called the energy of ionization

And if the energy is required to add an electron to an atom so we called it affinity of electron

Answer:

because the water/air needs to be pumped out.

Explanation:

hoped this helped! (just give it a 1 star if it didn't)

Answer: c

Explanation: effusion because there is a movement of a gas through a small opening into a larger volume

Answer:

[tex]\large \boxed{28 \, \% }[/tex]

Explanation:

magnesium  + nitrogen ⟶ Product

      13 g                5 g

Mass of product = 13 g + 5 g = 18 g

The product contains 5 g of nitrogen .

[tex]\text{Percent N} = \dfrac{\text{5 g}}{\text{18 g}} \times \, 100\% = \mathbf{28 \, \%}\\\text{The percent by mass of nitrogen is $\large \boxed{\mathbf{28 \, \% }}$}[/tex]

Answer:

The thermal decomposition of ammonium nitrate to produce dinitrogen monoxide and water. This reaction takes place at a temperature of 200-260°C.

[tex]7.408 \;X 10 ^ {-3} m^{-2} s^{-1}[/tex]  is rate of a reaction when k = 0.2, [A] = 3 M, [B] = 3 M, m = 1, n = 2 .

The rate at which the concentration of reactant or product participating in a chemical reaction alters is called the rate of reaction.

Rate of reaction = [tex]\frac{change \;in \;concentration}{time}[/tex] =  (mol/litre)/time.

m= 1 and n = 2

[tex]rate = K [A] [B]^2[/tex]

[tex]0.2 = K X 3 X 3 ^2[/tex]

K =   [tex]\frac{0.2 }{27 }[/tex]

K =   [tex]7.408 \;X 10 ^ {-3} m^{-2} s^{-1}[/tex]

Hence, [tex]7.408 \;X 10 ^ {-3} m^{-2} s^{-1}[/tex]  is rate of a reaction when k = 0.2, [A] = 3 M, [B] = 3 M, m = 1, n = 2 .

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Answer: 7.4 10-3

Explanation:

7.4 10-3 this is right ong

Answer:

Explanation:

Molecule of aluminium fluoride is more polar than molecule of aluminium chloride . It is so because fluorine is more electronegative than chlorine . On Pauling scale , the electronegativity of fluorine is 3.98 whereas that of chlorine is 3.16 . Hence in aluminium fluoride , there is stronger inter molecular bonding because of  more polar nature of molecules .  In aluminium chloride  , there is weaker  inter molecular bonding because of  comparatively  polar nature of molecules . Hence melting point of anhydrous aluminium fluoride is higher than that of anhydrous aluminium chloride .

Answer:

0.008303 mol and 0.0997 g

Explanation:

From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.022×10²³ atoms.

This implies that 1 mole of carbon also contains 6.022×10²³ atoms.

Next, we shall determine the mole of carbon that contains 5.0×10²¹ atoms. This can be obtained as follow:

1 mole of carbon contains 6.022×10²³ atoms.

Therefore, Xmol of carbon will contain 5.0×10²¹ atoms i.e

Xmol of carbon = 5.0×10²¹ / 6.022×10²³

Xmol of carbon = 0.008303 mole

Therefore, 0.008303 mole of carbon contains 5.0×10²¹ atoms.

Finally, we shall determine the mass of carbon. This can be obtained as follow:

Mole of carbon = 0.008303 mole

Molar mass of carbon = 12.01 g/mol

Mass of Carbon =.?

Mole = mass /Molar mass

0.008303 = mass of carbon/12.01

Cross multiply

Mass of Carbon = 0.008303 x 12.01

Mass of Carbon = 0.0997 g.