Calculate mole fraction of ethylene
Glycol in solution
containing 20% g C2H6O2 by mass.​

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 correct option is;

(B) 1 s², 2s², 2p⁶, 3s², 3p³

Explanation:

The electron configuration is the outline of the electron arrangement about a nucleus

In the systemic pattern of electron arrangement within an atom, there are, s, p, d, f orbitals

The maximum number of electrons in an s, p and d orbital = 2, 6, and 10 respectively

Based on Aufbau's principle the electrons are arranged based on the order of their energy level

The charge is presented by the number of electrons in the outermost shell, an element able to form an ion of charge of -3 will gain 3 electrons to complete its outermost shell

Among the options given, option B is the only option that has the capacity to take the electrons to complete the number of electrons in the p orbital outermost shell to 6 from 3, that is 3p³ + 3e⁻→ 3p⁶.

Answer:

Matter is any substance, if it is made up of only one kind of atom, then it is an element. Elements consists of atoms with the same weight and same number of protons in the nuclei.

Answer:

Basic

Explanation:

The pH scale is a scale that tells us about the concentration of hydrogen ions in a solution.

Acids have many hydrogen ions. Acids have a pH of less than 7.

Bases have fewer hydrogen ions and more hydroxide ions.  Bases have a pH of less than 14.

If the solution has a pH of exactly 7, then it is pure water. Water has the same concentration of hydrogen and hydroxide ions.

The antacid tablet has a pH of roughly 9.5 Since this is less than 14, but not equal to or less than 7, this must be an base. Therefore, it is considered to be in the basic range.

Answer:

9.5 is a base

Explanation:

A ph of less than 7 is an acid

7 is neutral

7 to 14 is a base

9.5 is a base

Answer:

a) 0°C

b) liquid

c) The energy supplied at 100°C is utilized in breaking the intermolecular forces in the liquid.

d) 100°C

e) gas

Explanation:

There are three States of matter; solid, liquid and gas. If we start heating 25g of ice in a beaker with a thermometer inserted into it, the ice will change from solid to liquid and finally to gas as the temperature increases.

At 0°C, the solid ice begins to melt and remains liquid between 0°C-100°C. This is called the liquid range of water. At 100°C, the heat supplied does not lead to further rise in temperature. The energy supplied is rather utilized in breaking the intermolecular forces in the liquid. This is known as the latent heat of vaporization. Above 100°C, the liquid is changed to vapour. Water vapour is commonly called steam.

Answer:

Percentage recovery of acetylferrocene = 81.6%

Explanation:

Mass of the sample mixture = 22.092 g

Ratio of mixture of acetylferrocene and ferrocene = 1 : 1

This means that the sample conatains equal amounts of acetylferrocene and ferrocene.

Therefore the mass of each sample in the mixture = 22.092 g / 2 = 11.046 g

Mass of acetylferrocene recovered = 9.017 g

Percentage recovery of acetylferrocene = (mass of recovered/ mass in sample) * 100%

Percentage recovery of acetylferrocene = (9.017 g / 11.046 g) *100%

Percentage recovery of acetylferrocene = 81.6%

Answer:

22

Explanation:

22

Answer:

it's a chemical Element

Explanation:

symbol He

atomic number 2.

Answer:

b. 2-4

Explanation:

Look at the slope of the line, between 0-2 and 4-6 the slope is only 10, but between 2-4 the slope is 20, so that's when the temperature is changing the fastest. In the same time it took for the water to increase by 20 degrees between 0-2 and 4-6, the temperature of the water increased by 40 degrees between 2-4 so that's when the change is the fastest.

Answer:

B) They will react because X and Y can share two pairs of electrons to become stable

Explanation:

The electron configurations of two elements x and y are given :

X: 1s2 2s2 2p6

Y: 1s2 2s2 2p6 3s2 3p6

The statement that is true for both the elements is that, they both will react as they both can share two pairs of electrons to become stable.

To become stable the outermost shell or p orbital should have 8 electrons, so element X  can gain 2 atoms to become stable.

Element Y can also react as it can also share two atoms to fulfill its 3p orbital and will stable.

Hence, the correct option is "B".

Answer:

Its 5

Explanation:

Answer:

B

Explanation:

The main aim of lab rules is to minimize the no of accidents

Answer:

1. A compound is a group of elements that cannot be separated by physical methods.

NaCl is a compound becuse it cannot be separated by physical methods.

It consists of postive and negative ions.

It can be separated only by chemical reactions.

2. (a) A is a mixture of iron and sulphur and it is in liq form.

(b) Gas B is hydrogen gas and it has sharp pungent irritating smell.

(c) It is a physical change.

Explanation:

Explanation:

If the reaction is endothermic as written, an increase in temperature will cause the forward reaction to occur

Answer:

1) 0.1077 moles

2) 137043.2 moles

3) 180.186 grams

4) 6.53×10²² molecules or formula units

5) 1.505×10²³ ions

6) 90.626 grams

7) 0.555 moles

Explanation:

1) The number of moles, n = Mass of the substance/(Molar mass of the substance)

The molar weight of PO₄⁻³ is 94.971 g/mol

The number of moles in 10.23 g of PO₄⁻³ is n =10.23/94.971 = 0.1077 moles

The number of moles in 10.23 g of PO₄⁻³ = 0.1077 moles

2) The number of molecules of Na₂CO₃ in one mole of Na₂CO₃ is given by the Avogadro's number, [tex]N_A[/tex] = 6.02 × 10²³ molecules

Therefore, the number of moles in 8.25 × 10²⁸ molecules of Na₂CO₃ is found by determining how many Avogadro's number of molecules are in 8.25 × 10²⁸ molecules of Na₂CO₃ as follows;

The number of moles in 8.25 × 10²⁸ molecules of Na₂CO₃ = (8.25 × 10²⁸)/(6.02 × 10²³) = 137043.2 moles

The number of moles in 8.25 × 10²⁸ molecules of Na₂CO₃ = 137043.2 moles

3) The molar mass of CH₂O = 30.031 g/mol

Therefore, the mass of 6 of CH₂O = 6 moles × 30.031 g/mol = 180.186 grams

The mass of 6 of CH₂O = 180.186 grams

4) The molar mass of NaCl = 58.44 g/mol

The number of moles of NaCl in 6.34 g of NaCl 6.34/58.44 = 0.1085 moles

1 formula unit of NaCl = 1 molecule of NaCl

The number of molecules in one mole of  a substance =  [tex]N_A[/tex] = 6.02 × 10²³

Therefore, the number of molecules in  0.1085 moles of NaCl = 6.02 × 10^(23) × 0.1085 = 6.53×10²² molecules or formula units

5) The number of ions per mole of any substance is give by Avogadro's number, [tex]N_A[/tex] = 6.02 × 10²³ ions,

The number of ions in 0.25 moles of Cu⁺² = 0.25×6.02 × 10²³ ions = 1.505×10²³ ions

The number of ions in 0.25 moles of Cu⁺² =  1.505×10²³ ions

6) The molar mass of CH₄ = 16.04 g/mol

The number of moles, n, in 3.4×10²⁴ = 3.4×10^(24)/(6.02×10^(23)) = 5.65 moles 5.65*16.04

The mass of 5.65 moles of CH₄ = 5.65 moles × 16.04 g/mol = 90.626 grams

The mass of 3.4×10²⁴ molecules of CH₄ = 90.626 grams

7) The density of water = 1 g/mL

The volume of the water 10 mL

The mass of the water = Volume × Density = 10 mL × 1 g/mL= 10 grams

The molar mass of water = 18.015 g/mol

The number of moles of water in 10 g  of water = mass/(Molar mass) = 10/18.015 = 0.555 moles.

Answer:

when the coal is heat with presence of oxygen it's called combustion...

Answer:

B) 82 protons

Explanation:

The number of protons for an element never change. 82 Is the atomic number for Pb which is how many protons it has. An isotope means it has more neutrons.

Answer:

the answer is 5.1 1049 mol.

Answer:

Thick deposits of sediments carried off of the shelf  

Explanation:

The continental rise is a thick deposit of sediments that accumulate between the continental slope and the abyssal plain

A is wrong. The area of land that drops toward the deep ocean basins is the continental slope.

B is wrong. The 75-mile shallow flat area just off coastlines is the continental shelf.

D is wrong. The surf area along coastlines is the surf zone .

Answer:

The chemical weathering of feldspar produces clay minerals

Explanation:

clay minerals form in the presence of water.

Answer:

4

Explanation:

none of them

they are compounds and mixtures

Answer:

4. none of them

Explanation:

Water is a compound.

Air is a mixture.

Soil is a mixture.

None of them are elements.

Answer:

About 2 liters

Explanation:

Since 1 gallon equals 3.785 liters, you figure out how many liters per week she uses by 3.785 x 0.75 which is 2.83875. Then divide that by 7 which is 0.405535 liters per day. Then multiply that by 5 days which is 2.027 liters in 5 days.

Answer:

Molarity = 2.0833 M (Approx)

Explanation:

Given:

Number of moles (n) = 0.25

Volume of solution = 120 ml = 0.12 L

Find:

Molarity

Computation:

Molarity = Number of moles (n) / Volume of solution.

Molarity = 0.25 / 0.12

Molarity = 2.0833 M (Approx)

Answer:

Both have densities greater than that of water

Explanation:

The ability of objects to either float or sink in a liquid depends on their relative densities.

If an object is denser than a liquid it will completely sink in it, but if the density of the object is less than that of the liquid, it will sink until the weight of liquid displaced is equal to the weight of the object, then it will finally float in that liquid.

In the case of the stone bead and iron beads dropped into a cup of water, hey both sank to the bottom because they are denser than water.

Answer:

Explanation:

GIven that:

The activation energy = 250 kJ

k₁ = 0.380 /M

k₂ = ???

Initial temperature [tex]T_1 =[/tex] 1001 K

Final temperature [tex]T_2 =[/tex] 298 K

Applying the equation of Arrhenius theory.

[tex]In \dfrac{k_2}{k_1 }= \dfrac{Ea}{R}( \dfrac{1}{T_1 }- \dfrac{1}{T_2})[/tex]

where ;

R gas constant = 8.314  J/K/mol

[tex]In \dfrac{k_2}{0.380 }= \dfrac{250 * 10^3}{8,314}( \dfrac{1}{1001 }- \dfrac{1}{298})[/tex]

[tex]In \dfrac{k_2}{0.380 }= -70.8655[/tex]

[tex]\dfrac{k_2}{0.380 }= e^{-70.8655}[/tex]

[tex]\dfrac{k_2}{0.380 }= 1.67303256 \times 10^{-31}[/tex]

[tex]{k_2}= 1.67303256 \times 10^{-31} \times {0.380 }[/tex]

[tex]{k_2}= 6.3575 \times 10^{-32}[/tex]  /M .sec

Half life:

At 1001 K.

[tex]t_{1/2} = \dfrac{In_2}{k_1}[/tex]

[tex]t_{1/2} = \dfrac{0.693}{0.38}[/tex]

[tex]t_{1/2} =[/tex] 1.82368 secc

At 298 K:

[tex]t_{1/2} = \dfrac{0.693}{6.3575 \times 10^{-32}}[/tex]

[tex]t_{1/2} =1.09 \times 10^{31} \ sec[/tex]

Answer:

The correct answer is - the second law of thermodynamics.

Explanation:

The second law of thermodynamics says that the in all heat energy exchange or transfer, and if there is no gain or lose of energy in a system, the potential energy of the particular state in that system will less than that of initial state of the system in any case.

It also suggests that the processes deals with the conversion of the heat energy are irreversible and the energy can be transfer from lower temperature system to higher temperate system without adding energy.

Thus, The fact that a heat pump requires energy to move heat from a colder object to a hotter object is a real life example of the second law of thermodynamics.

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

The question is incomplete, the complete question is;

To make a table of the elements, dimitri Mendeleev sorted the elements according to their?

Answer:

Atomic weights

Explanation:

Dimitri Medeleeve is a Russian scientist who worked assiduously on the project of developing a system of classifying all the elements. His periodic table was filled with spaces as many atoms weren't yet discovered. 'Eka' prefix was used to name some elements whose properties closely resembled that of their predecessors in Mendeleev's system of classification.

The dependence of the atomic properties on the weight of the atom was the basis for Mendeleeves' original classification. According to Medeleeve, elements having similar chemical properties are also expected to have similar atomic weights and their atomic weights was found to increase regularly.

The Mendeleeve concept of periodic arrangement of elements is the closest precursor of the modern periodic table as it is used in chemistry. Mendeleev arranged the elements in order of increasing relative atomic mass .

Answer:

ingredient. U.s unit. SI unit. SI unit(540)

flour. 2cups. ²/6. 180cups = 1.8×10²

milk. 2cups. ²/6. 180cups. =1.8×10²

eggs. 2. ²/6. 180eggs. =1.8×10²

melted butter. ⅓cup ¹/18. 30cups. =3×10¹

sugar. 1spoon. ¹/6. 90spoons. =9×10¹

baking powder 2spoons ²/6. 180spoons. =1.8×10²

salt. ½spoon. ¹/12. 45spoons. =4.5×10¹

Explanation:

1) to get the SI unit divide the U.S unit by 6

example:eggs = 2÷6. =²/6

2) to get the SI unit for 540 people ,multiply the SI unit by 540.

example:eggs ²/6×540. = 180

3)convert the answers to scientific notation

example:eggs =180. =1.8×10²