Which of the following elements is the largest in size
a. O
b. He
c. K
d. H

Answer:

The important characteristics of the particles of matter are – They are very, very small. They have spaces between them. They are constantly moving.

Answer:

They are very very small

Answer:

nucleons

Explanation:

The answer to the question is nucleons. Because there are both protons and neutrons in the nucleon, it will be heavier. Also, protons and neutrons are much heavier than the weight of an electron, because electrons float around the atom so it is not the answer. So, our final answer is actually option A.

Answer:

Magnesium (Mg)

Explanation:

The elements have very similar properties: they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure.

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Answer:

The answer is C. Magnesium(Mg)

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Answer:

8.35 × 10 ²² molecules

Explanation:

gram molecular weight of N2O4

= 2 × 14 + 4 × 16

= 28 + 64

= 92g

1 mole N2O4 has 6 × 10²³ molecules of N2O4 and weighs 92g

therfore,

92 g has = 6 × 10²³ molecules

12.8 g has =

[tex] \frac{6 \times 10 {}^{23}}{92} \times 12.8[/tex]

= 0.835 × 10²³

= 8.35 × 10 ²² molecules

Answer:

90grams

Explanation:

The reaction given in this question is as follows:

2H2 + O2 → 2H20

Based on this equation, 1 mole of oxygen gas (O2) produces 2 moles of water (H2O)

Hence, 2.50moles of oxygen gas will react with excess hydrogen gas to produce (2.5 × 2) = 5.0moles of water.

Using mole = mass/molar mass

Molar mass of water (H2O) = 1(2) + 16

= 18g/mol

5 = mass/18

mass = 18 × 5

mass of H2O = 90grams

Answer:

See explanation and image attached

Explanation:

The reactions of the alkynes involved are shown in the image attached to this answer.

First of all, the reaction of two equivalents of bromine with the alkyne converts it to a saturated compound as shown. One equivalent of HBr converts the alkyne to alkene while excess HBr completely reduces the compound to a saturated compound.

Li/NH3 reduces the alkyne to an alkeneby anti addition to the triple bond.

Reaction of the alkyne with H2O, H2SO4, HgSO4 converts it to an aldehyde as shown.

Answer:

The ratio of carbon and hydrogen atoms = 3.5 : 8

= 7 : 16

Then,the empirical formula is C7H16

Answer:

Einstein realized that the energy in electrons was caused by the frequency of light and not the intensity of light. This made him realize that he needed to explain the photoelectric effect.

Explanation:

Einstein realized that the photoelectric effect was a system that should be studied and explained in more depth, when he saw how the energy of electrons behaved in the presence of light. He saw that this energy depends entirely on the frequency of light and not on the intensity of light. From this observation, he realized that the photoelectric effect was essential for the production of an electric energy system, through light energy, such as solar energy.

It is important to note that the photoelectric effect refers to the ejection of electrons on a light surface that comes into contact with a light source.

Answer:

K should be large so the temperature change will be large enough to measure.

Explanation:

Let us recall that;

∆T = k m I

Where;

∆T= change in boiling point

K= freezing point constant

m= molality

i= Van't Hoff factor

Since the change in temperature depends on k, the larger the value of k the larger the temperature change(Ts - Tb). Hence; K should be large so the temperature change will be large enough to measure.

Ts= freezing temperature of pure solvent

Tb= freezing temperature of solution

Answer:

A. an acid

B. a base

C. conjugate base

D. conjugate acid

Explanation:

This question appears incomplete because it is starting with a "or".

However, the available question can still be answered.

An acid (according to "Bronsted-Lowry") is a chemical compound/specie that can donate hydrogen ion(s) in a reaction while a base is the compound/specie that can receive hydrogen ion(s). From this definition, it can be deduced that CH₃COOH (ethanoic acid) is an acid (weak acid) because it can donate an hydrogen ion while CH₃COO⁻ is a base because it can receive a hydrogen ion.

Also, a conjugate acid is the compound formed when an acid has donated a hydrogen ion to a base (i.e it is a base with hydrogen ion attached to it) while a conjugate base is the acid that has lost it's hydrogen ion. Thus, the conjugate acid in the question is CH₃OH while the conjugate base in the question is CH₃O⁻.

A. an acid

B. a base

C. conjugate base

D. conjugate acid

Answer:

For a: Lead iodide is a yellow precipitate.

For b: Barium sulfate is a white precipitate.

For c: Ferric hydroxide is a brown precipitate.

For d: Copper (II) hydroxide is a blue precipitate.

Explanation:

Precipitation reaction is defined as the reaction where a solid precipitate (solid substance) is formed at the end of the reaction. It is insoluble in water.

For the given options:

The chemical reaction between KI and lead (II) nitrate follows:

[tex]2KI(aq)+Pb(NO_3)_2(aq)\rightarrow PbI_2(s)+2KNO_3(aq)[/tex]

The iodide of lead is generally insoluble in water. Thus, lead iodide is a yellow precipitate.

The chemical reaction between barium chloride and sulfuric acid follows:

[tex]BaCl_2(aq)+H_2SO_4(aq)\rightarrow BaSO_4(s)+2HCl(aq)[/tex]

The sulfate of barium is insoluble in water. Thus, barium sulfate is a white precipitate.

The chemical reaction between NaOH and ferric chloride follows:

[tex]3NaOH(aq)+FeCl_3(aq)\rightarrow Fe(OH)_3(s)+3NaCl(aq)[/tex]

The hydroxide of iron is insoluble in water. Thus, ferric hydroxide is a brown precipitate.

The chemical reaction between NaOH and copper sulfate follows:

[tex]CuSO_4+2NaOH\rightarrow Cu(OH)_2+Na_2SO_4[/tex]

The hydroxide of copper is insoluble in water. Thus, copper (II) hydroxide is a blue precipitate.

(a) The yellow precipitate formed in the reaction between KI and Pb(NO3)2 would be PbI2 according to the equation:

[tex]Pb(NO_3)_2(aq) + 2KI(aq) ---> PbI2(s) + 2KNO_3(aq)[/tex]

(b) The white precipitate formed in the reaction between BaCl2 and H2SO4 would be  BaSO4 according to the equation:

   [tex]BaCl_2 (aq) + H_2SO_4 (aq) ---> BaSO_4 (s) + 2 HCl (aq)[/tex]

(c) The brown precipitate formed in the reaction between NaOH and FeCl3 would be Fe(OH)3 according to the equation:

[tex]FeCl_3 (aq) + NaOH (aq) ---> Fe(OH)_3 (s) + NaCl (aq)[/tex]

(d) The blue precipitate formed in the reaction between CuSO4 and NaOH would be Cu(OH)2 according to the equation:

[tex]CuSO_4(aq) + 2 NaOH (aq) ---> Cu(OH)_2 (s) + Na_2SO_4 (aq)[/tex]

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Answer:

Atmosphere to mmHg Conversion Example. Task: Convert 8 atmospheres to mmHg (show work) Formula: atm x 760 = mmHg Calculations: 8 atm x 760 = 6,080 mmHg Result: 8 atm is equal to 6,080 mmHg.

Explanation:

Answer:

"Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits, including apples, durians, pears, bananas, pineapples, and strawberries."

Explanation:

Answer:

A person doing physical work needs lots of good carbohydrates to keep their energy levels up and proteins to repair a muscle that might get wear and tear from overexertion. Carbohydrate will help the person work for more extended periods.

Answer:

= 35.7 amu

Explanation:

            Isotopic                fractional                                Wt Avg mass

          mass (amu)      abundance (= % / 100)       = Isotopic mass X (= % / 100)

X-35          35                         0.30                                           10.5 amu

X-36          36                         0.70                                           25.2 amu

__________________________________________________________

Average Atomic Mass of Element X = ∑ Wt. Avg. Masses = 35.7 amu

This is an acronym of the word Systeme International in French. Its International System of Units (SI) is a metric system that would be universally acknowledged as a measurement standard, and the further discussion can be defined as follows:

Conversion [tex]^{\circ} \ to \ K[/tex]:

let,

[tex]\to 0^{\circ}\ C + 273.15 = 273.15\ K\\\\[/tex]

So,

[tex]\to -35.903+273.15=237.247\ K[/tex]

Therefore, the final answer is "237.247".

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Answer:

6+9=15

mass number =15

mass number = no. protons + no. of neutrons

Answer:

B.9.710-11M

Explanation:

Answer:

Explanation:

This is a halogenation reaction i.e substitution or replacement of a single or more than a single hydrogen atom in the organic alkane compound with the halogen(here it is chlorine).

The chlorination of 1-chloro-2,2,3,3-tetramethylpentane under UV light resulted in the formation of five (5) dichloro derivatives which are shown in the image attached below.

Also, the compounds containing a stereocenter (i.e a location within the compound composing of various substituents in which the interchangeability of these substituents has the tendency of resulting into a stereoisomer) are indicated with an asterisk in the image below.

From the image below:

compound 1 ⇒  1,1-dichloro-2,2,3,3-tetramethylpentane = 2° C

∴

The given relative reactivity rate for 2°  = 3.6x

For compound 2 ⇒  1,4-dichloro-2,2,3,3-tetramethylpentane = 2°  = 3.6x

For compound 3 ⇒ 1,5-dichloro-2,2,3,3-tetramethylpentane = 1°  = 1x

For compound 4 ⇒ 1-chloro-2-chloromethyl-2,3,3-trimethylpentane

= 1°  = 1x

For compound 5 ⇒ 1-chloro-3-chloromethyl-2,2,3-trimethylpentane

= 1°  = 1x

As such, we have:

2(3.6x) + 3(1x) = 100

7.2x + 3x = 100

10.2x = 100

x = 100/10.2

x = 9.803°

∴

For compound (1) = 3.6(9.803) = 35.3%

For compound (2) = 3.6(9.803) = 35.3%

For compound (3) = 1(9.803) = 9.803°%

For compound (4) = 1(9.803) = 9.803°%

For compound (5) = 1(9.803) = 9.803°%

Explanation:

For this question, we apply the equation: Q = mCp AT Where m is the mass of the substance, Cp

is its specific heat capacity and AT is the

temperature change. Q = 896 x 0.45 x (5-94)

Q = -35884.8 Joules

So about -36 kilojoules of heat is released.

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Answer:

That is a " ball and stick " model which represents carbon compounds.

Explanation:

This is the answer. Hope it helps you find what you're looking for.

The question is incomplete, the common question is;

What intermolecular attractive force is primarily responsible for the solubility of chlorine, Cl2, in water?

a. dipole - dipole

b. hydrogen bonding

c. dipole-induced dipole

d. ion-dipole

e. ion-induced dipole

Answer:

dipole-induced dipole

Explanation:

We have to remember that water is a polar molecule hence it possesses a dipole moment. Its dipole moment is responsible for the ability of water to dissolve many substances.

On the other hand, Cl2 is a nonpolar molecule bound together by only weak dispersion forces.

Recall that dispersion forces involve transient appearance of a dipole in a molecule.

Water molecules can induce a dipole in Cl2 thereby causing the both molecules to interact and Cl2 dissolves in water.

Answer:

3 > 2> 1

Explanation:

Aromatic compounds undergo electrophilic substitution reaction with several electrophiles.

Some substituted benzenes are more reactive towards electrophilic aromatic substitution than unsubstituted benzene.

Certain groups of substituents increase the ease with which an aromatic compound undergoes aromatic substitution.

If we look at the compounds closely, we will notice that only toluene leads to easy reaction with CH3Cl / AlCl3. Thus is due to the +I inductive effect of -CH3 which stabilizes the negatively charged intermediate produced in the reaction.

answer

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Answer:

In the case of mixtures of ethanol and water, this minimum occurs with 95.6% by mass of ethanol in the mixture. The boiling point of this mixture is 78.2°C, compared with the boiling point of pure ethanol at 78.5°C, and water at 100°C. You might think that this 0.3°C doesn't matter much, but it has huge implications for the separation of ethanol / water mixtures. The next diagram shows the boiling point / composition curve for ethanol / water mixtures. I've also included on the same diagram a vapor composition curve in exactly the same way as we looked at on the previous pages about phase diagrams for ideal mixtures.

Answer:

19000 torr

Explanation:

From the question given above, the following data were obtained:

Initial volume (V₁) = 0.150 L

Initial pressure (P₁) = 1520 torr

Final volume (V₂) = 0.012 L

Temperature = constant

Final pressure (P₂) =?

The final pressure of the gas can be obtained by using the Boyle's law equation as illustrated below:

P₁V₁ = P₂V₂

1520 × 0.150 = P₂ × 0.012

228 = P₂ × 0.012

Divide both side by 0.012

P₂ = 228 / 0.012

P₂ = 19000 torr

Thus, the final pressure of the gas is 19000 torr

Answer:

Explanation:

·  44 g NaCl Explanation: The problem provides you with the molarity and volume of the target

The answer is rounded to two sig figs, the number of sig figs you have for the molarity of the solution.

The mass of a solute needed to prepare a solution with given volume is find by molarity. The mass of NaCl need to make a 138.1 mL solution of 0.190 M is 1.53 grams.

Molarity of a solution is a term to express its concentration. Mathematically, it is the ratio of no.of moles of solute to the volume of solution in litres.

Given that, the volume of solution is 138.1 mL. One litre solution is 1000 mL. Hence, 138.1 mL is 0.1381 L. The molarity of the solution is 0.190 M. From these data we can calculate the no.of moles of NaCl as below:

no.of moles = molarity × volume of solution in L

                    =  0.190 M × 0.1381 L

                    = 0.0262 moles.

This is the no.of moles required to make the solution.

Molecular mass of NaCl = 58.4 g/mol.

Thus mass of 0.0262 moles of NaCl = 0.0262  mol × 58.4 g/mol

                                                             = 1.53 g.

Therefore, the mass of NaCl required is 1.53 g.

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