Calculate the heat energy, in kJ, required to melt 1.0kg of ice at 0 degrees celcius.

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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

About 4/5.

Hope this helps.

Answer:  c

Explanation:

Answer:

Ammonium Ion (NH4+)

Explanation:

The chemical name for NH4 is ammonium.

Answer:

No observable change.

Explanation:

Copper renders dilute sulphuric acid passive, no reaction.

H2SO4+Cu-->CuSO4+H2

Explanation:

THIS IS THE CORRECT ANSWER

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:

12:35

Try it this way. egst11245

Answer:

A is mixture

B and C are compund

D and E are elements

F is also mixture

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

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:

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:

Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products.

A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.

Chemical reactions are an integral part of technology, of culture, and indeed of life itself. Burning fuels, smelting iron, making glass and pottery, brewing beer, and making wine and cheese are among many examples of activities incorporating chemical reactions that have been known and used for thousands of years. Chemical reactions abound in the geology of Earth, in the atmosphere and oceans, and in a vast array of complicated processes that occur in all living systems.

Explanation:

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Answer:

Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products

Explanation:

Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.

Answer:

In the case of an exothermic reaction, the reactants are at a higher energy level as compared to the products, as shown below in the energy diagram. In other words, the products are more stable than the reactants. Overall Δ H ΔH ΔH for the reaction is negative, i.e., energy is released in the form of heat.

Explanation:

Answer:

6,75 kilometres per hour

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:

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: A tick on a deer

Explanation:

because commensalism is a type of symbiotic relationship in which one species benefits, while the other species is neither harmed nor helped

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An example of commensalism is tick on a deer. Therefore, option A is correct.

Another sort of symbiotic interaction is commensalism, in which one organism benefits and the other does not in any way suffer. Golden jackals will pursue tigers as they hunt in order to consume the tigers' leftovers.

The term "commensalism" is derived from the word "commensal," which in human social interaction refers to "eating at the same table," and which itself is derived through French from the Medieval Latin term "commensalis," which refers to "sharing a table," from the prefix com-, which means "together," and mensa, which refers to "table" or "meal."

The simplest definition of commensalism is that it is a form of symbiosis in which one organism gains while the other neither gains nor suffers harm. The three primary forms of commensalism are phoresy, metabiosis, and inquilinism.

Thus, option A is correct.

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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.

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:

Explanation:

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

Answer:

Answer:

Don't plagiarize here.

Explanation:

Your online teacher knows that you are looking here for the answer!!!!

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:

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

Acids increase the [tex]H^+[/tex] concentration in solution. Therefore, the correct option is D.

One of their essential characteristics is the ability of all acids to increase the concentration of H+ ions (protons) in a solution. Acids are chemicals that when dissolved in water add protons to the solution. As a result of this proton donation, the amount of [tex]H^+[/tex]ions in the solution increases, thereby lowering the pH. It is important to remember that not all acids contain[tex]H_3O^+[/tex] ions directly; Instead, [tex]H^+[/tex] ions can react with water molecules to generate [tex]H_3O^+[/tex] ions (hydronium ions).

Therefore, the correct option is D.

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A stent is a small mesh tube that holds open passages in the body, such as weak or narrow arteries.

Explanation:

To open an artery near the heart

just took the quiz

Answer:

Mole of NaOH = 0.00308 mole

Explanation:

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

Volume = 22 mL

Molarity = 0.140 M

Mole of NaOH =?

Next, we shall convert 22 mL to L. This can be obtained as follow:

1000 mL = 1 L

Therefore,

22 mL = 22 mL × 1 L / 1000 mL

22 mL = 0.022 L

Finally, we shall determine the number of mole of NaOH in the solution. This can be obtained as shown below:

Volume = 0.022 L

Molarity = 0.140 M

Mole of NaOH =?

Molarity = mole / Volume

0.140 = Mole of NaOH / 0.022

Cross multiply

Mole of NaOH = 0.140 × 0.022

Mole of NaOH = 0.00308 mole

Thus, 0.00308 mole of NaOH is present in the solution.

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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Answer:

The number of moles in 89 grams of KCl is approximately 1.193 moles

Explanation:

A mole of an element or compound, is the quantity of the element or compound that contains 6.022 × 10²³ molecules of the element or compound, such that the molar mass of one mole is dependent on the mass of each molecule of the element or compound that make up the 6.022 × 10²³ particles

The given parameters are;

The mass of the KCl = 89 grams

The Molar mass, MW, of potassium, K = 39.1 g/mole

The Molar mass, MW, of chlorine, Cl = 35.5 g/mole

Therefore, given that KCl, has one K and one Cl, per mole, we have;

The Molar mass, MW, of potassium chloride, KCl = (39.1 + 35.5) g/mole = 74.6 g/mole

[tex]The \ number \ of \ moles, n=\dfrac{Mass}{Molar \ mass, MW}[/tex]

Therefore, the number of moles of KCl in 89 g, 'n' is given as follows;

n = (89 g)/(74.6 g/mole) ≈ 1.193 moles

The number of moles in 89 grams of KCl, n ≈ 1.193 moles.

Answer:

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

Explanation:

This is due to Asterric hinderance.