Delta S will be positive for the reaction ________. a. 2Hg (l) + O2(g) ----------> 2HgO (s) b. 2NO2 (g) -------> N2O4(g) c. CO2(g) --------> CO2(s) d. 2H2 (g) + O2(g) ------> 2H2O(g) e. BaF2(s) ------> Ba2 (aq) + 2F- (aq)

Answer:

0.56 M

Explanation:

Step 1: Given data

Step 2: Calculate the amount of reactant ([A]) after 28 seconds

For a first-order kinetics, we will use the following expression.

ln [A] = ln [A]₀ - k × t

ln [A] = ln 1.5 - 0.035 s⁻¹ × 28 s

[A] = 0.56 M

Answer:

[tex]C_{10}H_8[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to find the molecular formula of the given compound by firstly calculating both moles and grams of carbon in carbon dioxide and hydrogen in water, as the only sources of these elements derived from the compound x due to its combustion:

[tex]n_C=22.35gCO_2*\frac{1molCO_2}{44.01gCO_2}*\frac{1molC}{1molCO_2}=0.51molC\\\\m_C=0.51molC*\frac{12.01gC}{1molC} =6.10gC[/tex]

[tex]n_H=3.66gH_2O*\frac{1molH_2O}{18.02gH_2O}*\frac{2molH}{1molH_2O}=0.41molH\\\\m_H=0.41molH*\frac{1.01gH}{1molH}=0.41g[/tex]

Now, since the addition of carbon and hydrogen is about 6.50 grams, we infer the compound has no oxygen, that is why we now set the mole ratios in the empirical formula for both C and H as shown below:

[tex]C:\frac{0.51mol}{0.41mol}= 1.24\\\\H:\frac{0.51mol}{0.51mol}= 1\\\\C_{1.24}H[/tex]

Yet it cannot be decimal, that is why we multiply by 4 to get the correct whole-numbered empirical formula:

[tex]C_5H_4[/tex]

Whose molar mass is 64.09 g/mol, which makes the ratio of molar masses:

[tex]\frac{128.g/mol}{64.09g/mol} =2[/tex]

Therefore, the molecular formula is twice the empirical one:

[tex]C_{10}H_8[/tex]

Regards!

Answer:

The reaction between hydrogen and fluorine.

Explanation:

The balanced chemical equation of the reaction is:

[tex]H_2(g)+F_2(g)->2HF(g)[/tex]

From the balanced chemical equation, it is clear that:

1 mole of [tex]H_2[/tex] gas reacts with one mole of [tex]F_2(g)[/tex] and forms 2 moles of HF(g).

Answer:

1s22s22p6

Explanation:

Neon is an element in the periodic table and has an atomic number of 10, which means it has 10 protons in its nucleus and thus since the number of protons and electrons is the same then it has 10 electrons.

Therefore, it has 2 electrons in the first energy shell and 8 electrons in the second energy shell. To elaborate further, the first shell has a single s-sub shell that contains a single s-orbital that can hold two electrons. The second energy shell has a single s-sub-shell whose s-orbital will occupy 2 electrons, and also has a p-orbital which can hold 6 electrons, making the second shell to have 8 electrons.

Answer:

[tex][O_2]_{eq}=0.030M[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to solve this problem by firstly writing out the mathematical expression for the concentration of oxygen at equilibrium, given the initial one and the change due to the reaction extent:

[tex][O_2]_{eq}=0.050M-x[/tex]

Whereas [tex]x[/tex] can be found considering the equilibrium of SO3:

[tex][SO_3]_{eq}=2x=0.040M[/tex]

Which means:

[tex]x=\frac{0.040M}{2} =0.020M[/tex]

Thus, the equilibrium concentration of oxygen gas turns out:

[tex][O_2]_{eq}=0.050M-0.020M=0.030M[/tex]

Regards!

Answer:

The right solution is "[tex]8.5\times 10^{-19} \ joule[/tex]".

Explanation:

As we know,

1 mole electron = [tex]6.023\times 10^{23} \ no. \ of \ electrons[/tex]

Total energy = [tex]513 \ KJ[/tex]

                     = [tex]513\times 1000 \ joule[/tex]

For single electron,

The amount of energy will be:

= [tex]\frac{513\times 1000}{(6.023\times 10^{23})}[/tex]

= [tex]8.5\times 10^{-19} \ joule[/tex]

Answer:

2 HCl + Ba(OH)₂ ⇒ BaCl₂ + 2 H₂O

Explanation:

In a complete neutralization reaction, an acid reacts with a base to form neutral salt and water. To form barium chloride, hydrochloric acid (acid) reacts with barium hydroxide  (base). The balanced chemical equation is:

2 HCl + Ba(OH)₂ ⇒ BaCl₂ + 2 H₂O

The question is incomplete, the complete question is;

If you were to perform a recrystallization experiment and wanted to form very large crystals of pure substance, what would be the most UNfavorable conditions?

A. Fast cooling solution, use of an anti-solvent, rapidly evaporating solution

B. Slowly cooling solution, slowly evaporating solvent

Answer:

Fast cooling solution, use of an anti-solvent, rapidly evaporating solution

Explanation:

Recrystallization is a process of obtaining pure crystals from solution. The procedure involves dissolving the crystals in a solution in which they are soluble at high temperature but insoluble at low temperature.

As the solution cools, the pure crystals are obtained from the solution.

The solvent to be used must be a slow cooling, slow evaporating solvent so that the crystals can be efficiently recovered from solution.

Answer:

The rusting of iron is spontaneous at low temperatures.

Explanation:

The given chemical reaction is:

4Fe(s) + 3O2(g) ----> 2Fe2O3(s) [rust]

The rusting of iron is a chemical reaction in which iron reacts with oxygen in presence of moisture and forms iron oxide.

This reaction takes place in a faster rate when there is low temperatures in the atmosphere.

When temperature is low, the moisture in the atmosphere is more and hence, rate of rusting is more.

hola, esta pregunta es bastante difícil pero está bien, no lo sé, lo siento :) :)

All the options are solved and answer is written below

A reaction between two or more compounds to form products made after chemical change is called a chemical reaction.

It is given that

A chemical reaction was carried out by mixing 25 g of pure CaCO₃ and 0.75 mole of pure HCl

CaCl₂ , H₂O and CO₂  are the products obtained.

CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O

Mole ratio CaCO₃ : HCl : CaCl₂ : H₂O = 1 : 2 : 1 : 1

Molar mass of CaCO₃  = 100 g/mol

Molar mass of HCl  = 36.5 g/mol

Molar mass of H₂O = 18 g/mol

Molar mass of CaCl₂= 110.98 g/mol

Moles of CaCO₃ = 25/100 = 0.25 moles

Moles of HCl present = 0.75 mole

For 0.25 moles of CaCO₃ 0.5 moles of HCl is required , as the moles of HCl is present in excess therefore

a. CaCO₃ is the limiting reactant

b. mass of CaCl₂ produced

Moles of CaCl₂  produced = 0.25 moles

1 mole means 110.98 gm

0.25 mole means 0.25* 110.98 = 27.74 gm

c. moles of water molecules formed

for 0.25 moles of CaCO₃ 0.25 moles of water will be formed

d.Volume of Co produced at STP

PV = nRT

P= 1 atm

V=?

R = 0.0821 atm L/K/mol

V = 0.25 * 0.0821 * 273 /1

V = 5.6 liter

e. The mass of NaOH required to absorb CO₂ produced in the reaction

Ratio of NaOH:CO₂ = 2 :1

0.5 moles will be required , i.e.

0.5 *40

20 grams of NaOH will be required.

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Answer:

the electrolysis reaction is a non- spontaneous reaction

Explanation:

Since electrons flow from it, the anode in an electrolytic cell is positive, while the cathode is negative when electrons flow into it. The device functions like a galvanic cell in that direction. In an electrolytic cell, an external voltage is applied and that is what causes a non spontaneous reaction

Answer:

Ionic bond: Ionic bonds are bonds involving the attraction between oppositely-charged ions.

Covalent bond: Covalent bonds form when electrons are shared between atoms and are attracted by the nuclei of both atoms.

Co ordinate bond separately:  a covalent bond in which both electrons are provided by one of the atoms. dative bond.

Explanation:

Hope this helps!

Answer:

a) 3H₂ (g) + N₂ (g) → 2NH₃ (g)

b) 2Na₂O₂ + 2H₂O → 4NaOH + O₂

General Formulas and Concepts:

Atomic Structure

Aqueous Solutions

Explanation:

a)

When we write this chemical reaction, we know that hydrogen and nitrogen are diatomic elements. Ammonia you just have to remember the chemical compound formula for. So our unbalanced equation would be:

H₂ (g) + N₂ (g) → NH₃ (g)

Now to balance this equation, we see that we have an uneven amount of hydrogens and nitrogens on both sides of the rxn. Let's balance out the nitrogens first by multiplying the products by 2:

H₂ (g) + N₂ (g) → 2NH₃ (g)

We see that now we have the number of nitrogens balanced on both sides, but our hydrogens are still unbalanced. Let's balance those by making the reactants the same number as our products:

It looks like we need to multiply 3 on the reactant hydrogens:

3H₂ (g) + N₂ (g) → 2NH₃ (g)

And we have our balanced formula!

b)

Same concept as A.

Recall how to write chemical compounds. The charge of sodium (Na) is +1 and the charge for polyatomic ion peroxide (O₂²⁻) is -2. Also recall the charge for polyatomic ion hydroxide (OH)m which is -1:

Sodium peroxide = Na₂O₂

Water = H₂O (standard knowledge)

Sodium hydroxide = NaOH

Oxygen gas = O₂

Write out our unbalanced rxn:

Na₂O₂ + H₂O → NaOH + O₂

Right away we can see that it is definitely unbalanced. We can see that we have an odd number of oxygens on both sides. We don't like odds here, so let's multiply 2 to the sodium peroxide and to make it even:

2Na₂O₂ + H₂O → NaOH + O₂

We can see that we have an even amount of oxygens on the reactant side. Now we have to balance the number of sodiums on the product side:

2Na₂O₂ + H₂O → 4NaOH + O₂

We now have the sodiums balanced. Moving onto the hydrogens. 2 on the reactant side and 4 on the product side:

2Na₂O₂ + 2H₂O → 4NaOH + O₂

We now have the hydrogens balanced. When we move on to oxygens, we can see that the number of oxygens have the same number of moles on both sides, and that would be our balanced rxn.

Answer:

Solution given:

a) hydrogen gas + nitrogen gas gives ammonia.

Balanced chemical equation:

[tex]\boxed{\bold{\green{3H_{2}+N_{2}\rightarrow 2NH_{3}}}}[/tex]

when pure and dry Nitrogen and Hydrogen gas is passed in the ratio 2:3 at 450°C temperature 200-900 ATM pressure in tye presence of iron as catalyst and molybdenum as promotor which forms Ammonia.

b) sodium peroxide + water gives sodium hydroxide + oxygen gas.

Balanced chemical equation:

[tex]\boxed{\green{\bold{3NaO_{2}+2H_{2}O \rightarrow 4NaOH +O_{2}}}}[/tex]

When sodium peroxide is combined with hot water double displacement reaction takes place and forms sodium hydroxide and oxygen gas along with heat.

Answer:

When the temperature of the reaction is > 958.1K

Explanation:

A reaction is spontaneous when ΔG < 0.

We can solve this question finding the temperature at which ΔG < 0 using the equation:

ΔG = ΔH - TΔS

As ΔG < 0

ΔH < TΔS

206kJ/mol < T*0.215kJ/K.mol

958.1K < T

When the temperature of the reaction is > 958.1K, the reaction is spontanous because ΔG < 0.

Explanation:

The chemical formula of an ionic compound can be written by using the symbols of the respective cations and anions.

The overall charge on the molecule should be zero.

Hence, the total charge of cations=total charge of anions.

The symbols of the given molecules are shown below:

sodium chloride  ---- NaCl

magnesium chloride ---[tex]MgCl_2[/tex]

calcium oxide ---- CaO

lithium phosphide----[tex]Li_3P[/tex]

aluminum sulfide ----- [tex]Al_2S_3[/tex]

calcium nitride---- [tex]Ca_3N_2[/tex]

Answer:

89,6/22,4 =4(mol)

Explanation:

There are approximately 1.089 moles of oxygen gas present in the sample at STP.

At STP (Standard Temperature and Pressure), the conditions are defined as follows:

Temperature (T) = 0 degrees Celsius = 273.15 Kelvin

Pressure (P) = 1 atmosphere (atm) = 101.325 kPa = 1013.25 hPa

Now, to find the number of moles of oxygen gas (O2) present in the sample, we can use the ideal gas law:

PV = nRT

Where:

P = pressure (in atm)

V = volume (in liters)

n = number of moles

R = ideal gas constant = 0.0821 L.atm/(mol.K)

T = temperature (in Kelvin)

Given:

V = 89.6 L (volume at STP)

T = 273.15 K (STP temperature)

Let's plug in the values and solve for n (number of moles):

n = PV / RT

n = (1 atm) × (89.6 L) / (0.0821 L.atm/(mol.K) × 273.15 K)

n = 1.089 moles

So, there are approximately 1.089 moles of oxygen gas present in the sample at STP.

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Answer:

Halogens

HalogensHalogens are the most reactive nonmetals on the periodic table.

Answer:

A) halogen

Explanation:

halogen are highly reactive because they are all electro negative

Answer:

a. glucose in water( solution)

b. smoke in air (colloids)

c. carbon dioxide in air (solution)

d. milk( colloids)

Explanation:

A solution is said to be formed when a solute dissolves in a solvent to form a homogeneous mixture. The solute particles are less than 10^-9m in size. Familiar solutions are those where the solute are dissolved in a liquid solvent. When the liquid water, the solution is known as an aqueous solution. A typical example is (glucose in water). In some other cases, the apparent solution of a solute in a solvent is accompanied by a chemical reaction and this is often known as a chemical reaction. A typical example is (carbon dioxide in air).

Colloids are also known as false solutions. Here, the individual solute particles are larger than the particles of the true solution, but not large enough to be seen by the naked eye. When a light beam is placed beside a beaker containing a colloid, the light rays of the beam can be clearly seen. This shows that it exhibits the Tyndall effect while a solution dosent exhibit such.

In a colloid, the liquid solvent is more appropriately know as the DISPERSION medium while the solid solute particles constitute the DISPERSED substance. This can either be solid, liquid or gas.

For example:

--> smoke in air : Dispersion medium is gas while the dispersed substance is solid.

--> milk: Dispersion medium is liquid while the dispersed substance is liquid.

El hidrógeno es el elemento químico de número atómico 1, representado por el símbolo H. Con una masa atómica de 1.00784 u  ​ es el más ligero de la tabla periódica de los elementos. Por lo general, se presenta en su forma molecular, formando el gas diatómico H₂ en condiciones normales.

Answer:

Following are the solution to the given points:

Explanation:

For point A:

For point B:

In point 3, the mixture was added to 100°C, which implies that the granular material flows and deforms, enabling it to become elongated. This is termed solid-state crystalline such that grains are flexible, but this material contaminates numerous little crystalline that has spheres when we cool down in point  4 polymers. It forms therefore an unstructured solid, which then in point 4 is higher in particles and less pliable in orderly atoms.

For point C:

In point 2, the specimen gets forced at room temperature to organize a huge molecule in an ordinary and crystal fashion and therefore is transparent due to highly crystalline atoms in point 2 of the PET sample.

In point 4, however, we notice how amorphous, firm but not crystalline develops. It's why light tends to disperse over many cereal limits, since many microscopic crystallines, therefore dispersion, PET in point 4 is translucent.

Answer:

Kp = \frac{P(NH_{3}) ^{4} P(O_{2}) ^{5}}{P(NO) ^{4} P(H_{2}O)^{6}}

Explanation:

First, we have to write the balanced chemical equation for the reaction. Nitrogen monoxide (NO) reacts with water (H₂O) to give ammonia (NH₃) and oxygen (O₂), according to the following:

NO(g) + H₂O(g) → NH₃(g) + O₂(g)

To balance the equation, we add the stoichiometric coefficients (4 for NH₃ and NO to balance N atoms, then 6 for H₂O to balance H atoms and then 5 for O₂ to balance O atoms):

4 NO(g) + 6 H₂O(g) → 4 NH₃(g) + 5 O₂(g)

All reactants and products are in the gaseous phase, so the equilibrium constant is expressed in terms of partial pressures (P) and is denoted as Kp. The Kp is expressed as the product of the reaction products (NH₃ and O₃) raised by their stoichiometric coefficients (4 and 5, respectively) divided into the product of the reaction reagents (NO and H₂O) raised by their stoichiometric coefficients (4 and 6, respectively). So, the pressure equilibrium constant expression is written as follows:

[tex]Kp = \frac{P(NH_{3}) ^{4} P(O_{2}) ^{5}}{P(NO) ^{4} P(H_{2}O)^{6}}[/tex]

Answer:

you first get the unbalanced equation to show the various products and reactants. then, you write down the atoms in each element(quantity). add the coefficients so it's equal on both sides, and get state of matter

Explanation:

Answer:

Option C (a higher; the same) is the appropriate response.

Explanation:

Given:

Temperature,

T = 300 K (both [tex]N_2[/tex] and [tex]H_2[/tex])

As we know,

Average speed of a molecule,

⇒ [tex]\bar v=\sqrt{\frac{8RT}{\pi M} }[/tex]

Thus, the average speed of [tex]N_2[/tex] will be lower as its molar mass is greater than [tex]H_2[/tex].

Now,

⇒ [tex]Average \ kinetic \ energy = \frac{3}{2} \ KT[/tex] (not depend on molar mass)

Hence, it will be the same.

The other three alternatives aren't connected to the scenario given. So the above is the correct answer.

The question is incomplete, the complete question is;

Identify the highest energy molecular process that occurs when a molecule absorbs a microwave photon

a) electronic excitation

b) bond breakage

c) molecular vibration

d) molecular rotation

Answer:

molecular rotation

Explanation:

Microwaves are part of the electromagnetic spectrum. They are lower energy, lower frequency radiation.

When molecules absorb infrared radiation, they transition between the rotational states of the molecule.

Hence, the highest energy molecular process that occurs when a molecule absorbs a microwave photon is molecular rotation.

Answer:

-203 kJ/mol

Explanation:

Step 1: Given data

Step 2: Calculate the standard Gibbs free energy of the reaction (ΔG°)

We will use the following expression.

ΔG° = ΔH° - T × ΔS°

ΔG° = (-314 kJ/mol) - 298 K × (-0.372 kJ/K.mol) = -203 kJ/mol

By convention, when ΔG° < 0, the reaction is spontaneous.

Answer:

because some bacteria change the ph of the teeth and leads to tooth cavitiew

Answer:

122

Explanation:

because after exercises heart beat increases

Answer:

I think option A is right answer

Answer:

Gold

Explanation:

We are given that

Mass of sample ,m=385 g

Volume ,V=20mL

We have to find the coin is gold or yellow brass.

We know that

Density=[tex]\frac{Mass}{volume}[/tex]

Using the formula

[tex]Density=\frac{385}{20}g/mL[/tex]

[tex]Density=19.25g/mL[/tex]

[tex]Density\approx 19.3g/mL[/tex]

Density of coin=19.3g/mL

Density of gold=19.3g/mL

Hence, the coin is gold.

Answer:

Mass percent of KCl is 2.61 %

Explanation:

Our solute is KCl

Our solvent is water

m means molality (moles of solute in 1kg of solvent)

1 kg = 1000 g

0.35 m means that 0.35 moles of KCl are contained in 1000g of solvent

We determine mass of solute: 0.35 mol . 74.55 g/mol = 26.09 g

Total mass of solution is: mass of solute + mass of solvent

26.09 g + 1000 g = 1026.09 g

Mass percent of KCl = (mass of KCl/ mass of solution) . 100

(26.09 / 1026.09) . 100 =  2.61 %