Which statement correctly compares and contrasts the information represented by the chemical formula and model of a compound? Both show how the atoms in a compound are connected. Models show how the atoms in a compound are connected. Chemical formulas show how the atoms in a compound are connected.

Answer:

Explanation:

The total energy or intrinsic energy of a system is called the enthalpy. In thermochemistry, we have two types of enthalpy changes which are:

For the freezing of water, the enthalpy change is an exothermic one. Exothermic changes are designated as negative. In this chemical change, heat is liberated to the surroundings and this leaves the environment at a much higher temperature. In freezing, the enviroment gains more heat as the material begins to cool to lower temperature.

Entropy is the degree of randomness or disorderliness of a system. When a phase change occurs from liquid to solid, freezing takes place. Such a change increases the orderliness of a system and entropy diminishes. Here, entropy is negative.

The free energy is a measure of the energy a system that does useful work. Free energy depends on enthalpy, entropy and temperature of a system. For phase changes such as freezing of water, the value of free energy change is 0.

For this process, an increases in temperature makes it non-spontaneous. Increasing temperature would alter the course of the reaction and makes it exothermic. For entropy, increasing temperature would increase entropy and therefore, the reaction would not be feasible.

Temperature would mostly affect the free energy. An increase in temperature would increase the value of entropy change and the reaction would not be spontaneous. With falling temperature value, the reaction becomes more spontaneous and favored.

Answer:

B

Explanation:

bevxjs zkbxkxbxo xkd ksbslbsi ixbxksbzo

Answer:

copper carbonate

Explanation:

Answer:

The correct answer is D: the reactants are generally two ionic compounds in aqueous solution.

Explanation:

A type of reaction in which two reactants participate and exchange ions with each other as the reaction proceeds. Such type of reaction is known as a double displacement reaction. In double displacement reaction, the product formed is precipitate.

Below is the pathway of the double displacement reaction:

AB + CD → AD + CB

In double displacement reaction usually, ionic compounds are involved. The bond formation between the reacting species may be ionic or covalent in nature.

Final answer:

In a double-replacement reaction, two ionic compounds in aqueous solution exchange ions to form two new products, requiring one product to be insoluble for a reaction to occur.

Explanation:

In a double-replacement reaction, the reactants are generally two ionic compounds in aqueous solution. These reactions involve the exchange of anions and cations between the reactants to form two new products. For a reaction to occur, one of the products must be insoluble in water, forming a solid precipitate, or a molecular compound such as water; if both products remain soluble, no reaction has taken place. Energy in terms of heat or light is not a characteristic feature of double-replacement reactions, unlike some other types of chemical reactions.

Examples include reactions where a precipitate, gas, or molecular compound forms, all of which signify a chemical change. The general formula for these reactions is AB + CD → AD + BC, indicating the switch between anions and cations.

Answer:

S(s) + O2(g) → SO2(g)

The correct chemical equation that represents the burning of sulfur to form sulfur dioxide is S(s) + O2(g) -> SO2(g). This equation illustrates that one mole of sulfur reacts with one mole of oxygen to produce sulfur dioxide.

The question is asking for the correct formula equation which represents the burning of sulfur to produce sulfur dioxide. The burning of sulfur in the presence of oxygen (O2) results in the formation of sulfur dioxide (SO2). This process can be represented by the following chemical equation:

S(s) + O2(g) —> SO2(g)

This shows that one mole of sulfur (S) reacts with one mole of Oxygen (O2) to produce one mole of sulfur dioxide (SO2).

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Answer:

the strongest intermolecular forces

Explanation:

The broken lines depicts hydrogen bonding. Hydrogen bonds are intermolecular forces are they are very strong bonds. These bonds are special dipole-dipole attractions between polar molecules in which hydrogen atom is directly joined to a highly electronegative atom usually oxygen or nitrogen or fluorine.

The broken lines shows the intermolecular attraction.

Answer:

3rd is the correct answer

(NH[tex]_4[/tex])[tex]_2[/tex]SO[tex]_4[/tex] is the chemical formula for ammonium sulfate. Therefore, the correct option is option D.

A chemical formula is a way to describe the chemical ratios of the atoms that make up a specific chemical compound or molecule in chemistry. Chemical element symbols, numbers, as well as occasionally other symbols, including such parentheses, dashes, brackets, commas, and plus (+) and minus (-) signs, are used to represent the chemical elements.

They can only include one typographic row of symbols, and they can additionally include subscripts or superscripts. A chemical formula has no words and is not the same as the chemical name. A chemical formula does not equal a complete chemical structural formula, despite the fact that it may suggest some basic chemical structures. (NH[tex]_4[/tex])[tex]_2[/tex]SO[tex]_4[/tex] is the chemical formula for ammonium sulfate.

Therefore, the correct option is option D.

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Answer:

In the chemical industry, lithium-based batteries are working most efficiently and replacing nickel-cadmium batteries. To study a redox reaction in a lithium battery let's take the example of Lithium Cobalt Oxide(LiCoO2).

Following is the overall reaction taking place in Lithium Cobalt Oxide battery. Reduction and oxidation takes place at Cathode and Anode respectively. that is why it is called a redox reaction.

Reaction at cathode:

Cathode: CoO2+Li+e−→ LiCoO2 (Reduction)

Reaction at Anode:

Anode: LiC6→ C6+Li++e− (Oxidation)

Overall reaction:  

LiC6 + CoO2→ C6 + LiCoO2

Answer:

1) 0.0625  g.

2) 0.0125 g.

Explanation:

1) A solution of NaOH has a concentration of 25.00% by mass. What mass of NaOH is present in 0.250 g of this solution?

mass% of NaOH = [(mass of NaOH)/(mass of solution)] x 100.

mass% of NaOH = 25.0%, mass of NaOH = ???  g, mass of solution = 0.250 g.

∴ mass of NaOH = (mass% of NaOH)(mass of solution)/100 = (25.0%)(0.250 g)/100 = 0.0625  g.

2) What mass of NaOH must be added to the solution to increase the concentration to 30.00% by mass?

We can use the relation:

mass% of NaOH = [(mass of NaOH)/(mass of solution)] x 100.

mass% of NaOH = 30.0%, mass of NaOH = ???  g, mass of solution = 0.250 g.

∴ mass of NaOH = (mass% of NaOH)(mass of solution)/100 = (30.0%)(0.250 g)/100 = 0.075  g.

∴ The mass of NaOH should be added = 0.075 - 0.0625 = 0.0125 g.

Answer:

1) 0.0625  g.

2) 0.0125 g.

3) 80.0 g

Explanation:

edge

Answer:

used to date rocks and other objects based on the known decay rate of radioactive isotopes.

Explanation:

Different methods of radiometric dating can be used to estimate the age of a variety of natural and even man-made materials.

Answer:

Hydrogen bonding attracts water molecules to one another and slows the rate of evaporation- last choice

Answer: Option (a) is the correct answer.

Explanation:

Vapor pressure is defined as the pressure exerted by vapors or gas on the surface of a liquid.

So, the greater the intermolecular forces present between the molecules of a substance, lower the vapor pressure.

Evaporation is defined as the ability of a substance's molecules to readily convert into vapors.

In water molecules, there exists hydrogen bonding which is a strong bonding. As a result, molecules are not able to readily convert into vapors due to which no force will exert easily on the surface of water molecules.

Hence, water will have an unusually low vapor pressure.

Thus, we can conclude that water have an unusually low vapor pressure for a liquid because the oxygen-hydrogen bond in a water molecule is unusually strong, which decreases the rate of evaporation.

Answer:

The three models describes the structure of an atom based on different views.

Explanation:

Plum pudding model described the atom of consisting of negatively charged electrons embedded in positively charged substrates; this was later proven to be false. The Bohr's model described the electrons in an atom to orbit round the nucleus at different energy, the closer it's to the nucleus, the lesser the energy it needs. The Rutherford model claims the the nucleus of the atom contains protons and neutrons which forms the mass of the atom, the electrons surrounds the nucleus and it forms the volume of the atom.

The atom has been the smallest unit of matter. It has been revealed with the varies studies and models proposed to deliver the accepted and well illustrated model.

The Plum pudding model has been the first atomic model proposed by J.J. Thomson. The  Rutherford model has been the well illustrated model of the atom.

The Plum pudding model has been proposed by J.J. Thomson, the Nuclear model by Rutherford, and the Bohr model has been proposed  by Bohr.

The atomic models have been proposed for the atom. All the models have been focused with a central positive nucleus, and negative electrons outside the nucleus.

The plum pudding model considered electrons to be distributed unequally outside the nucleus. The Nuclear model has been considered electrons to be present outside the nucleus in the orbital shells. The Bohr model has been able to explain the quantum address of the electron.

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Answer: If a substance is the limiting reactant, then it will be completely used by the time the reaction completes because it is the reactant that reacts completely and the reaction stops after it is completely used up.

Explanation:

Limiting reagent is a reagent as it limits the formation of product and Excess reagent is the reagent which is preset in excess.

For example: if 0.75 moles of HCl and 1.5 moles of magnesium are reacted together.

[tex]Mg(s)+2HCl(aq)\rightarrow MgCl_2(aq)+H_2(g)[/tex]

According to stoichiometry:

As 2 mole of [tex]HCl[/tex] reacts with 1 mole of [tex]Mg[/tex]

0.75 moles of [tex]HCl[/tex] will react with =[tex]\frac{1}{2}\times 0.75=0.38moles[/tex] of [tex]Mg[/tex]

[tex]HCl[/tex] is a limiting reagent as it limits the formation of product and Mg is an excess reagent as (1.5-0.38)=1.12 moles of magnesium are left unreacted.

Answer:  If a substance is the limiting reactant, then it will be fully consumed by the time the reaction completes because it is the reactant that reacts completely and the reaction cannot proceed further.

Answer: the answer is C!

Heat is released during the process

Explanation:

This means that 285.8 kJ/mol is evolved when one mole of water is formed.

The term enthalpy of formation has to do with the energy that is released or absorbed when a molecule of water if formed from its constituents.

The fact that the enthalpy of formation of water is -285.8 kJ/mol implies that 285.8 kJ/mol is evolved when one mole of water is formed.

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Answer:

50%

Explanation:

You would have to do 15 divided by 30 x 100 to get 50

Percentage Yield = Actual Yield divided by Theoretical Yield

Hope this is right and helpful

Answer:

Explanation:

I usually just use approximate values for the elements on the periodic table. The reason for that is that everyone uses a different periodic table. Some are rounded others are more precise. Redo this problem with better numbers for the elements.

N = 14

H = 1

N2H4 = 2*14 + 4*1  

N2H4 = 28 + 4 = 32

If you are given 31 grams of N2H4 then the formula is

mols = given mass / molecular mass

mols = 31 / 32

moles = 0.97  

Now you have a problem . Is the answer 1.0 or is 0.9?

I think I would pick 1.0

Answer: In Thomson's model, the atom is composed of electrons called “corpuscles,” he calls the model the plum pudding model of the atom

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Answer:

The answer is:

The correct option is option C.

[tex]V=36L[/tex]

To calculate the volume of the gas sample, we need to use the Ideal Gas Law, this equation is used to relate the pressure, the volume, the mass and the temperature of a gas, so, we can isolate the volume from it.

The Ideal Gas Law equation is equal to:

[tex]PV=nRT[/tex]

Where,

P is the pressure (in atm)

V is the volume (in liter)

n is the mass of the gass (in mole)

T is the temperature of the gass (absolute temperature)

So, from the statement we know that:

[tex]Pressure=1.3atm\\Temperature=298K\\n=1.9moles\\R=0.082057\frac{L.atm}{mol.K}[/tex]

Then, substituting and calculating we have:

[tex]PV=nRT\\\\V=\frac{nRT}{P}=\frac{1.9moles*0.082057\frac{L.atm}{mol.K}*298K}{1.3atm}=35.74L[/tex]

Now, rounding to the nearest whol number we have that the volume is equal to 36 L.

Hence, the correct option is option C.

Have a nice day!

Answer:

No heat is released.

Explanation:

A substance absorbs heat when it melts.

The formula for the heat absorbed is

[tex]q = m\Delta_{\text{fus}}H[/tex]

Data:

m = 10 g

\Delta_{fus) H=\text{334 J/g}

Calculations:

[tex]q = 10 \times 334 = \text{3340 J = 3.34 kJ}\\\text{The ice }\boxed{\textbf{absorbs 3.34 kJ}} \text{ when it melts}.[/tex]

The energy released when the given mass of the ice melts is 3,340 J.

The energy released when the given mass of the ice melts is determined by taking the product of mass and heat of fusion of the ice.

Q = mH

where;

Substitute the given parameters and solve for the energy released when the ice melts.

Q = 10 x 334

Q = 3,340 J

Thus, the energy released when the given mass of the ice melts is 3,340 J.

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Answer:

D

Explanation:

O

2  is the limiting reagent because the least moles of this are used in the reaction.

Final answer:

Oxygen (O2) is the limiting reactant in the reaction 4NH3 + 5O2 = 4NO + 6H2O when 4 grams of O2 and 2 grams of NH3 are used, as it has a smaller ratio of moles to its coefficient in the balanced equation compared to NH3. So the correct option is D.

Explanation:

The limiting reactant in the chemical reaction 4NH3 + 5O2 = 4NO + 6H2O can be determined by calculating the moles of the reactants and comparing their mole ratio with the stoichiometry of the balanced equation. First, calculate the moles of NH3 and O2 using their molar masses (NH3: 17 g/mol, O2: 32 g/mol):

Next, divide the moles of each reactant by their respective coefficients in the balanced equation:

Since the ratio for NH3 is larger than the ratio for O2, O2 is the limiting reactant. This means that not all of the NH3 will be used up in the reaction.

Answer:

"A physicist is someone who studies or completes research into physics. There are many subsets of physics, ranging from very small particle physics to very large cosmology, or study of the universe. There are a wide number of physics courses and majors available. These courses are available at the undergraduate, graduate, and doctoral levels."

                                           "What Is a Physicist? - wiseGEEK"

Physicists study natural phenomena through experiments and observational examinations, creating theories that explain how the world works. For example, physicists studied the phenomenon of gravity and came up with a generally functioning law, the law of gravity. In addition, physicists study phenomena associated with the universe, the motion and mass of objects, electricity, and various other natural phenomena.

Answer:

12000 Liters or 12 × 10^6 cubic centimeters

Explanation:

Multiply the volume value by 264.172

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Answer:

Using the table on the right, complete each unit conversion by typing in the correct answer.

85.0 kg =

187 lb    

5.000 km =

3.125 mi

8.000 fl oz =

236.8 mL

14.600 oz =

414.64 g

Explanation:

Bolded ones are the answers for all of the questions!! You're welcomeee

Final answer:

To convert 85.0 kg to pounds, you multiply by the conversion factor of 2.205 lb/kg. The result should maintain the original number of significant figures, which in this case is three, so following the significant figures rule, the answer is rounded to 187 lb.

Explanation:

The student has asked for the conversion of 85.0 kilograms (kg) to pounds (lb). To perform the conversion, the appropriate conversion factor needs to be applied. Given that 1 kg is approximately equivalent to 2.205 lb, you would multiply the mass in kilograms by this conversion factor to find the equivalent weight in pounds. It's important to keep in mind the significant figures of the inexact number when calculating the final answer.

Here's the calculation:

85.0 kg x 2.205 lb/kg = 187.425 lb

However, since we are starting with 85.0 kg (which has three significant figures), our final answer should also have three significant figures. Therefore, we round 187.425 to 187 lb to match the significant figures.

Answer:

A very large amount of energy is produced from a very small mass.

Explanation:

Nuclear energy is produced either by fusion or fission. The former is the fusion of lighter atoms into heavier elements while the latter is the splitting of a heavier atom into lighter atoms. Both produce tremendous amounts of energy. Fusion, causes compaction of mass while fission reduces it. Fusion does not produce radioactive particles while fission does (alpha and beta particles and neutrons).

Answer:

=2.7 g/cm³

=2700 kg/m³

Explanation:

Density is a ratio of the mass of an object to its volume.

The volume of the named block of aluminium is calculated as follows:

90mL - 75mL= 15mL

15mL = 15 cm³

The mass = 40.5 g

Therefore ρ=m/v

=40.5g/15cm³

=2.7 g/cm³

=2700 kg/m³

Answer:

False

Explanation:

Max Planck's theory of the duality of energy shows that the frequency radiation "v" can be regenerated only if an oscillator of such frequency has acquired the minimum energy required to initiate oscillation. At low temperatures, there is not enough energy available to induce high-frequency oscillations; in this way, the object does not regenerate ultraviolet radiation, ending the ultraviolet catastrophe.

Albert Einstein used this Max Planck hypothesis to explain the results obtained in his work on the photoelectric effect in 1905. Einstein did not refute Max's theory.

Albert Einstein's discovery of quanta does not disprove Max Planck's hypothesis about the dual nature of energy   i.e. False

Max Planck's hypothesis ( quantum hypothesis ) on the radiation of a black body states that energy from light can only be absorbed and radiated in discrete bundles ( quanta ), and this formed the basis on which Albert Einstein explained the results he obtained from his photo electric effect experiment he carried out.  therefore we can conclude that Einstein did not disprove Max Planck's hypothesis.

Hence we can conclude that Albert Einstein's discovery of quanta did not disprove Max Planck's hypothesis about the dual nature of energy.

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Final answer:

The coefficients that will balance the equation N₂ + H₂ → NH₃ are 1 for N₂, 3 for H₂, and 2 for NH₃.

Explanation:

Chemical equations express chemical reactions using symbols and formulas. Reactants on the left side transform into products on the right side. Balancing ensures conservation of mass. Coefficients in chemical equations represent the numerical ratios of reactants and products. They ensure the conservation of mass and atoms. Adjusting coefficients balances the equation, reflecting the correct stoichiometry of the reaction.

The coefficients that will balance the skeleton equation N₂ + H₂ → NH₃ are: 1 for N₂, 3 for H₂, and 2 for NH₃. The coefficients of a balanced equation represent the mole ratio required for the reaction to occur. In this case, one mole of N₂ reacts with three moles of H₂ to produce two moles of NH₃.

Answer:

A) it can measure data by experiments

Explanation:

Chemistry is testable which means that when a scientist claims a certain observation happening in chemical sciences then other chemists globally can verify that observation by carrying out independent experiments. When similar observations are made only then there is a consensus in the scientific community.

Therefore, chemistry is testable

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Answer:

The total charge of cations plus anions must equal zero.

Explanation:

The result Barium sulfide which is arrived upon because the total charge of cation plus anions =0

+2+(-2)=0 as seen above. The product is an electrically neutral compound.

Ba²⁺+ S²⁻⇒BaS

The product is a solid which is in the looks of black ash.

Answer:

The answer is: The total charge of cations plus anions must equal zero.

Hope this helped :)

Explanation:

Answer:

0.5

Explanation:

1 mole of ammonium nitrate contains 2 moles of nirogen

1 mole of nitrogen converts to 0.5  moles of ammonium nitrate

the conversation factor is 0.5

Answer:

The conversion factor is 0.5, with which we have to multiply moles of nitrogen to convert it into moles of ammonium nitrate.

Explanation:

As given the molecular formula of ammonium nitrate is NH₄NO₃

There are two nitrogen in each molecule.

thus in each mole of ammonium nitrate there are two moles of nitrogen present in it.

It means if there are two moles of nitrogen the mole of ammonium nitrate will be one

If there is one mole of nitrogen the moles of ammonium nitrate is 0.5.

So if we wish to convert moles of nitrogen to moles of ammonium nitrate we have to multiply the moles of nitrogen with 0.5.

The conversion factor is

[tex]\frac{molesofammoniumnitrate}{molesofnitrogen}=0.5[/tex]