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Answer:

1.B

2.C

3.D

Explanation:

In the first question, the valence in XH4 belongs to the X. So when it reacts with oxygen with always a valence of two, they cancel out remaining 2 making it XO2.

In the second question the 2 belongs to Y as we all know Sodium is atomic number 11 with a valence of one, so they exchanged valence.

When Y2 reacts with chlorine with atomic number 17 and valence 1,they exchange valencies making it YCl2.

In the third question, 2belongs to Y, so when it reacts with aluminum with atomic number 13 and valence 3,they exchange valencies making it Al2Y3

Answer:

98L is the volume of the gas

Explanation:

To solve this question we need to find  the moles of O2 + moles HCl. With these moles and PV = nRT we can find the volume as follows:

Moles O2: 3.0mol

Moles HCl:

50.0g * (1mol/36.5g) = 1.37 moles HCl

Total moles:

3.0mol O2 + 1.37 mol HCl = 4.37 moles

PV = nRT

V = nRT/P

Where V is volume in L, n are moles = 4.37mol, R is gas constant = 0.082atmL/molK, T is absolute temperature = 273.15K at STP, P = 1atm at STP

V = 4.37mol*0.082atmL/molK*273.15K / 1atm

V = 98L is the volume of the gas

Answer: NH3 (g) would be considered a base because it is a proton acceptor.

Explanation: at the end of the system, NH3 (g) turns into NH4+ (aq) which means it has accepted a hydrogen ion.

According to Bronsted- Lowry concept, bases are proton acceptors. Here, NH₃ is accepting a proton from HSO₄⁻. Hence, NH₃ is a base and option B is correct.

There are various concepts to define acids and bases. According to Bronsted - Lowry concept, acids are proton donors and bases are proton acceptors.

Acids forms their conjugate base by donating a proton and bases form their conjugate acid by accepting the proton from acid. Here, HSO₄⁻ acts as the acid to donate electron to ammonia.

Hence, NH₃ acts as the base to accept the proton from the acid and forms its conjugate acid NH₄⁺ (ammonium ion). Therefore, option B describes the action of NH₃.

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Your complete question is given below:

Answer:

The new substance will need more energy to form its chemical bonds than the old substance will release. ... More energy will be released from the old substance than the new substance will need to form its chemical bonds.

Explanation:

This is the answer I got. Hope it's really helpful

Answer:

"Which is evidence that a chemical reaction has likely occurred?"

The correct answer would be,

B. the formation of a precipitate

Explanation:

Got it right on my test, have a great day!

Answer:

80÷4=20 Helium atoms

Explanation:

Because one helium atom is a quarter of of one bromine atom

Answer:

Ammonium Ion (NH4+)

Explanation:

The chemical name for NH4 is ammonium.

Respuesta:

Cr₂S₃O₁₂

Explicación:

Primer paso: Dividir el porcentaje en masa de cada elemento por su masa atómica

Cr: 26,53/52 = 0,510

S: 24,52/32 = 0,766

O: 48,96/16 = 3,06

Segundo paso: Dividir todos los números por el más pequeño (0,510)

Cr: 0,510/0,510 = 1

S: 0,766/0,510 = 1,5

O: 3,06/0,510 = 6

Tercer paso: Multiplicar todos los números por algún número que haga que todos sean enteros (2)

Cr: 1 × 2 = 2

S: 1,5 × 2 = 3

O: 6 × 2 = 12

La fórmula empírica es Cr₂S₃O₁₂.

Answer: The empirical formula of the compound becomes [tex]Cr_2S_3O_{12}[/tex]

Explanation:

The empirical formula is the chemical formula of the simplest ratio of the number of atoms of each element present in a compound.

Let the mass of the compound be 100 g

Given values:

% of Cr = 26.53%

% of S = 24.52%

% of O = 48.96%

Mass of Cr = 26.53 g

Mass of S = 24.52 g

Mass of O = 48.96 g

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

To formulate the empirical formula, we need to follow some steps:

Molar mass of Cr = 52 g/mol

Molar mass of S = 32 g/mol

Molar mass of O = 16 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of Cr}=\frac{26.53g}{52g/mol}=0.510 mol[/tex]

[tex]\text{Moles of S}=\frac{24.52g}{32g/mol}=0.766 mol[/tex]

[tex]\text{Moles of O}=\frac{48.96g}{16g/mol}=3.06 mol[/tex]

Calculating the mole fraction of each element by dividing the calculated moles by the least calculated number of moles that is 0.510 moles

[tex]\text{Mole fraction of Cr}=\frac{0.510}{0.510}=1[/tex]

[tex]\text{Mole fraction of S}=\frac{0.766}{0.510}=1.5[/tex]

[tex]\text{Mole fraction of O}=\frac{3.06}{0.510}=6[/tex]

Multiplying the mole fraction of all the elements by 2, in order to make it as a whole number

[tex]\text{Mole fraction of Cr}=(2\times 1)=2[/tex]

[tex]\text{Mole fraction of S}=(2\times 1.5)=3[/tex]

[tex]\text{Mole fraction of O}=(2\times 6)=12[/tex]

The ratio of Cr : S : O = 2 : 3 : 12

Hence, the empirical formula of the compound becomes [tex]Cr_2S_3O_{12}[/tex]

Answer:

See explanation

Explanation:

9g of water contains : 9g/18 g/mol = 0.5 mole of water

1) 2 moles of hydrogen yields 2 moles of water

x moles of hydrogen yields 0.5 moles of water

x= 2 × 0.5/2 = 0.5 moles of hydrogen

Mass of hydrogen = 0.5 moles × 2 = 1 g of hydrogen

2) Number of moles of Al(OH)3 = 468 g/ 78 g/mol = 6 moles

2 moles of Al(OH)3 yields 3 moles of H2O

6 moles of Al(OH)3 yields 6 × 3/2 = 9 moles of H20

Mass of water =9 moles × 18 g/mol = 162 g of water

3) There are 13 oxygen atoms in the compound.

Mass of each oxygen atom = 16 g

Total mass of oxygen atoms = 13 × 16 = 208 g

Answer:

16.7 %(m/m)

Explanation:

The percent by mass of a solution (% m/m) is defined as 100 times the ratio of the mass of solute (The substance in the lower amount, NaCl) and the mass of the solution = Mass solute + Mass Solvent (water).

Mass Solution:

100g NaCl + 500g water = 600g solution

Mass Percent:

100g NaCl / 600g solution * 100

= 16.7 %(m/m)

Answer:

A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur.

Explanation:

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Answer:

3.98dm³

Explanation:

Using combined gas law equation:

P1V1/T1 = P2V2/T2

Where;

P1 = initial pressure (kPa)

P2 = final pressure (kPa)

V1 = initial volume (dm³)

V2 = final volume (dm³)

T1 = initial temperature (K)

T2 = final temperature (K)

According to the provided information in this question:

V1 = 3.5dm³

V2 = ?

P1 = 101 kPa

P2 = 85.0 kPa

T1 = 23.0°C = 23 + 273 = 296K

T2 = 10.0°C = 10 + 273 = 283K

Using P1V1/T1 = P2V2/T2

101 × 3.5/296 = 85 × V2/283

353.5/296 = 85V2/283

Cross multiply

296 × 85V2 = 353.5 × 283

25,160V2 = 100,040.5

V2 = 100,040.5 ÷ 25,160

V2 = 3.98dm³

Answer: On increasing temperature at which adsorption is carried out decreases the extent of physisorption.

Explanation:

An adsorption where molecules of the adsorbate are placed or held on the surface of adsorbent by Vander waals forces is called physisorption.

There is basically physical bonding between the molecules of gas to the surface of a solid or liquid.

Physisorption is reversible in nature and occurs at low temperatures.

It is not specific in nature which means that all gases are adsorbed on the surface of every solid substance to some extent.

Thus, we can conclude that on increasing temperature at which adsorption is carried out decreases the extent of physisorption.

One-fourth of the original amount of an isotope is present after a period of two half-lives as each time the amount is reduced by half.

Isotopes are defined as substances having same number of protons but different number of neutrons.Number of protons is characteristic for determining position of elements in the periodic table.

Since,all isotopes have the same number of protons and hence have same position.They have similar chemical properties as they have same number of electrons.

They find applications in the field of nuclear medicine and oil and gas research . There are 2 types of isotopes : stable and unstable

Unstable isotopes are radioactive and are called as radioisotopes.Some of these isotopes are man -made and hence also called as artificial isotopes.Every element has an isotope which is either man-made or natural .

Many properties of isotopes depend on mass which is measured in atomic mass unit. The difference in actual mass and mass number is called mass defect.

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Answer:

See explanation

Explanation:

The can chiller has a cooling system which expels heat around the immediate vicinity of the can chiller.

Let us remember that convection is a mode of heat transfer that occurs as a result of the actual movement of the particles of a substance. In this case, we are going to consider the movement of air molecules.

As the can chiller expels heat, the air molecules around the can chiller become heated and less dense and begin to move away from the can chiller. They are quickly replaced by cold denser air.

This process of cycling of hot/cold air molecules is known as a convection current. It is set up as a result of the working of the can chiller.

Answer:

okay no problem I will be there

Answer:

15/16

Explanation:

We need to find the number of moles of hydrogen and number of moles of ethane present.

Since we have the same mass, m for both substances, the number of moles of hydrogen, n = m/M where M = molar mass of hydrogen molecule

Since hydrogen is H₂, M = 2 × 1 g/mol = 2 × 1 g/mol = 2 mol.

n = m/M

n = m/2

Also, number of moles of ethane, n' = m/M' where M' = molar mass of ethane.

Since ethane is C₂H₆, M' = 2 × 12 g/mol + 6 × 1 g/mol = 24 g/mol + 6 g/mol = 30 g/mol

n' = m/M'

n' = m/30

The total number of moles of gas present is thus n" = n + n' = m/2 + m/30 = (15m + m)/30 = 16m/30

The mole fraction of hydrogen is thus number of moles of hydrogen/total number of moles = n/n" = m/2 ÷ 16m/30 = m/2 × 30/16m = 15/16

Also, since the partial pressure due to hydrogen, P = mole fraction × total pressure, P'

P/P' = mole fraction = 15/16

So, The fraction of the total pressure exerted by hydrogen is 15/16

Answer:

No observable change.

Explanation:

Copper renders dilute sulphuric acid passive, no reaction.

H2SO4+Cu-->CuSO4+H2

Explanation:

THIS IS THE CORRECT ANSWER

Answer: Chromatography is a technique for the separation of a mixture. The mixture is dissolved in a fluid (gas, solvent, water, ...) called the mobile phase, which moves it through a system (a column, a capillary tube, a plate, or a sheet) on which is fixed a material called the stationary phase.

Explanation:

Answer:

0.3 sec : -0.4 m

0.5 sec: -1.2 m

0.7 sec: -2.3 m

Explanation:

0.3 sec: 1/2(-9.3 m/s^2)(0.3 s)^2 = -0.4 m

0.5 sec: 1/2(-9.3 m/s^2)(0.5 s)^2 = -1.2 m

0.7 sec: 1/2(-9.3 m/s^2)(0.7 s)^2 = -2.3 m

Answer:

Primary carbocations are most stable, Secondary carbocations are more stable, tertiary carbocations are least stable.

Explanation:

This is due to Asterric hinderance.

Answer:

Weight = 500 Newton

Explanation:

Given the following data;

Acceleration due to gravity = 10N/Kg

Weight can be defined as the force acting on a body or an object as a result of gravity.

Mathematically, the weight of an object is given by the formula;

[tex] Weight = mg [/tex]

Where;

Note: In order to calculate the weight of a mass, it's required that the mass of an object or body is given.

However, in this particular question it was omitted in error and as such i would assume a value.

Substituting into the formula, we have;

[tex] Weight = 50 * 10 [/tex]

Weight = 500 Newton

Answer:

Technically a microorganism or microbe is an organism that is microscopic. The study of microorganisms is called microbiology. Microorganisms can be bacteria, fungi, archaea or protists. The term microorganisms does not include viruses and prions, which are generally classified as non-living.

Answer:

The molecules move slower than the temp of 50°c and their average kinetic energy decreases.

Explanation:

kinetic energy cannot increase as temperature is reduced. molecules will still move with reduced motion.

Answer:

Valency can be defined as a measure of the combining power of a chemical element with other atoms to form a molecule or chemical compound.

Explanation:

An atom can be defined as the smallest unit comprising of matter that forms all chemical elements. Thus, atoms are basically the building blocks of matters and as such determines or defines the structure of a chemical element.

Generally, atoms are typically made up of three distinct particles and these are protons, neutrons and electrons.

In Chemistry, electrons can be defined as subatomic particles that are negatively charged and as such has a magnitude of -1.

Valence electrons can be defined as the number of electrons present in the outermost shell of an atom. Valence electrons are used to determine whether an atom or group of elements found in a periodic table can bond with others. Thus, this property is typically used to determine the chemical properties of elements.

Valency can be defined as a measure of the combining power of a chemical element with other atoms to form a molecule or chemical compound.

Typically, valency is measured by the amount of hydrogen atoms that a chemical element can combine with or displace to form a molecule or chemical compound.

For example, Oxygen has a total number of eight (8) electrons while neon has total number of ten (10) electrons. Therefore, an atom of oxygen is able to gain (accept or receive) two (2) more electrons in order to have the same electron arrangements as the noble gas i.e an atom of neon with an atomic number of 10.

Answer:

Explanation:

B.Rice grains, which have accidentally been mixed with flour

Carbon has an atomic number of 6 so its electron configuration will be 1s² 2s² 2p². It has two orbitals as indicated with the 2 as its period number with the outer orbital have 4 valence electrons. So carbon is in the p-orbital, period 2 and in group 4.

Explanation:

From the word equation, it shows that when copper oxide reacts with sulphuric acid, a double replacement reaction will occur, where copper and sulphate forms a bond with each other, and so do water.

The reaction of copper oxide with sulphuric acid to form copper sulphate and water can be written as follows: [tex]CuO + H_{2}SO_{4} \rightarrow CuSO_{4} + H_{2}O[/tex]

In a balanced chemical reaction all the reactants will be in a correct stochiometric ratios where, each elements have to be equal in number on both side of the reaction.

The given reaction is an example of double displacement reaction in which two species are displaced. Here, oxygen from copper oxide goes to water and sulphate group from sulphuric acid displace to copper sulphate.

This product of this reaction i.e., copper sulphate have cyan color and this reaction is exothermic.  Thus, the balanced reaction can be written as follows;

[tex]CuO + H_{2}SO_{4} \rightarrow CuSO_{4} + H_{2}O[/tex]

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