which sector is targeted for the application of hydrogen fuel cells

Answer:

it's exothermic reaction, becasue it have negative energy and the temperature increases

Answer: B.) -12.4

Explanation: This is because the sign of heat transfer is determined by the system's perspective. In this case, the system is releasing heat to the surroundings, which means that heat is flowing out of the system, making the heat transfer negative. The magnitude of the heat transfer is 12.4 J.

The depression in freezing point of water here is 3.33 °C. Then the molality of the solution is 1.79. From number of moles of solute is calculated as 0.0161. Then , the molar mass of the solute is 62.11 g.

The addition of a non-volatile salt into a solvent will decrease the freezing point of the solution than the pure solvent. The change in freezing point is proportional to the molality of the solution.

ΔTf = Kf m

Kf is called molal depression constant.

Kf for water = 1.86 °C Kg/mol

given ΔTf = 3.33 (0 - (-3.33))

then m = ΔTf /Kf =  3.33/ 1.86 °C Kg/mol = 1.79

Now, mass of water= 9 g = 0.009 kg

then number of moles = molality × mass of solvent

n = 0.009 kg × 1.79 = 0.0161.

mass of solute taken = 1 g

then, molar mass = 1/0.0161 = 62.11 g.

Therefore, the molar mass of the solute is 62.11 g.

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The denstiy of the gold bar of mass 3300 g is 18.3 g/cm³.

Density is the ratio of mass and volume.

To calculate the density of the bar gold, we use the formula below.

Formula:

Where:

From the question,

Given:

Susbtitute these values into equation 1

The bar is not a pure gold.

Hence, the denstiy is 18.3 g/cm³.

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Answer:

An exothermic process releases heat, causing the temperature of the immediate surroundings to rise. An endothermic process absorbs heat and cools the surroundings.”

Answer:

All abiotic and biotic factors of the zoo are part of the ecosystem.

Explanation:

An ecosystem is composed of all the living and non-living things in a particular area, and how they interact with one another. All the items listed, including rocks, water, trees, grass, monkeys, and birds, are part of the zoo ecosystem as they interact with each other and the environment.

The mass of the HNO3 solution was found to be 0.882 g and the titer of the NaoH solution was 0.016g/cm^3.

what was NaoH ?

The inorganic chemical sodium hydroxide, widely known as lye and caustic soda, has the formula NaOH. It is a white solid ionic compound that contains sodium cations Na+ and hydroxide anions OH.

Sodium hydroxide is a caustic base and alkali that degrades proteins at room temperature and can inflict serious chemical burns. It collects moisture and carbon dioxide from the air and is extremely soluble in water. It creates a succession of NaOHnH2O hydrates. Between 12.3 and 61.8 °C, the monohydrate NaOHH2O crystallises from water solutions. This monohydrate is frequently used in commercially available "sodium hydroxide," and published data may refer to it instead of the anhydrous component.

As one of the most basic hydroxides, sodium hydroxide is commonly employed in conjunction with neutral water.

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Answer:

The date when the animal was buried can be estimated by using the decay rate of Carbon-14. The half-life of Carbon-14 is 5,730 years, so the date when the animal was buried can be estimated by taking the half-life and multiplying it by the logarithm of the ratio of the 14C/12C ratio of the bone and the 14C/12C ratio of a living plant or animal. In this case, 5,730 years x log(0.477) = 45,906 years ago.

Explanation:

The molality of the sodium ions and the sulfate ions are  44.5 and 10.66 respectively.

How do you calculate molality?

The total number of moles of solute per litre of solution is defined as the molarity of a specific solution. Because, unlike mass, the volume of a system changes with changes in physical circumstances of the system, the molality of a solution is reliant on changes in physical qualities of the system such as pressure and temperature. M, which stands for molarity, represents molarity. The molarity of a solution is one molar when one gramme of solute is dissolved in one litre of solution. As we know, the solvent and solute combine to create a solution, hence the total volume of the solution is measured.

molality of sodium was

=480.57/10.781

=44.5

molality of sulfate was

=28.93/2.712

=10.66

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Answer: 5.5769g/ml^3

Explanation:

density=mass/volume

.78g/ml=4.350g/volume

Answer:

3,3 dihydroxy

Oh group attach with that benzene ring

The number of atoms in the reactants and products of each reaction is the same. The last option.

The law of conservation of matter states that during chemical reactions, matter can neither be created nor destroyed but can be converted from one form to another. This law is also applicable to energy and atoms during chemical reactions.

In other words, all chemical reactions, as a rule of thumb, obey the law of conservation. Thus, for any chemical reaction:

Therefore, the statement that supports the student's conclusion that the two reactions follows the law of conservation of matter would be that the number of atoms in the reactants and products of each reaction is the same.

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Ionization constant of a reaction is the ratio of the molar concentration of product to that of reactants. For the given  reaction, the ionization constant is 155.8 .

A compound or element gets ionized to form its anion or cation by the gain or lose of electrons.

Here, acetic acid, CH₃COOH ionizes to form hydronium ion and acetate ion. The ratio of product of molar concentrations of products to the product of molar concentrations of the reactants is called the reaction constant.

The ionization constant of the given reaction is written as:

K = [H₃O]⁺ [CH₃COO-]/[CH₃COOH]

Given, [CH₃COOH] = 0.8 M

[CH₃COO-] = 16.4 M

and  [H₃O]⁺ = 7.6 M.

then, K = 7.6 M × 16.4 M/ 0.8 M = 155.8

Therefore, the ionization constant of the reaction is 155.8.

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In order to lower the temperature of 350 mL of water from 24°C to 6°C, we need to calculate the amount of heat energy that needs to be removed from the water. We can use the formula:

Q = mcΔT

where Q is the heat energy, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.

The specific heat capacity of water is 4.184 J/g°C. Since the density of water is 1.0 g/mL, the mass of 350 mL of water is 350 g.

Q = (350 g) (4.184 J/g°C) (18°C)

Q = 30,276 J

To remove this much heat energy, we can use ice to cool the water. The heat of fusion of water is 333.55 J/g, which is the amount of heat energy required to melt one gram of ice at 0°C.

Q = (m)(333.55 J/g)

m = Q / 333.55 J/g

m = 30,276 J / 333.55 J/g

m = 90.4 g

So, 90.4 grams of ice at 0°C would have to melt to lower the temperature of 350 mL of water from 24°C to 6°C.

Answer:

Plasma globes use high voltage, low current electrical discharges to ionize gases, typically a mixture of noble gases such as argon and neon, inside the globe. The electrical discharge excites the gas atoms, stripping them of their electrons to create a cloud of positively charged ions and negatively charged electrons, also known as plasma. The electrical discharge arcs between the electrodes in the globe, creating the colorful, dancing lights that are characteristic of plasma globes.

Explanation:

Answer:

Explanation:

Force = Mass x Acceleration

(20 - 5)N = 5kg x Acceleration

Acceleration = 15/5

                     = 3 N/kg

The volume required of 0,3 N. acid solution to neutralize solution containing 0,32 g of NaOH in 40 cm³ is 26.66cm³.

N1V1 = N2V2

normality = molarity x basicity

For sulfuric acid, the basicity is 2.

∴N1=0.3N

V1=?

Normality of NaOH is [0.32/(40×40)]×1000

N2=0.2×1=0.2N

V2=40ml

0.3 x V1 = 0.2 x 40

V1 = 26.6 cm³

It is defined as the number of moles per liter of solution. It is used to measure gram equivalents to the total volume of the solution. It is used to measure the ratio of the number of moles in the total volume of the solution. The unit of normality is N or eq L-1.

The standard concentration (normality, CN) of a solution is always greater than or equal to the molarity (molarity, CM) of the solution.

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The name of the compound is calcium chloride and the chemical formula of the compound is CaCl₂.

Chemical  formula is a way of representing the number of atoms present in a compound or molecule.It is written with the help of symbols  of elements. It also makes use of brackets and subscripts.

Subscripts are used to denote number of atoms of each element and brackets indicate presence of group of atoms. Chemical formula does not contain words. Chemical formula in the simplest form  is called empirical formula.

It is not the same as structural formula and does not have any information regarding structure.It does not provide any information regarding structure of molecule as obtained in structural formula.

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Answer: Cobalt,Titanium,Potassium

Explanation:

If an element has 4 electron layers can be well understood from their electronic configuration :-

Cobalt -> [Ar] 3[tex]d^{7}[/tex] 4[tex]s^{2}[/tex]

Titanium -> [Ar] 3[tex]d^{2}[/tex] 4[tex]s^{2}[/tex]

Carbon -> [He] 2[tex]s^{2}[/tex] 2[tex]p^{2}[/tex]

Potassium -> [Ar] 4[tex]s^{1}[/tex]

Answer:

g = 9

Explanation:

5.22 = 2.61(g - 7)  ==> solve for g

5.22 / 2.61 = 2.61(g - 7) / 2.61  ==> divide both sides by 2.61 to isolate g

2 = g - 7  ==> simplify

9 = g  ==> add 7 on both sides

g = 9

Answer:

Here is the order of increasing boiling point and increasing solubility in water for the substances you listed:

-2-Methylpropane < -2-butanol < -2-pentanol < -2-propanol

Explanation:

-2-Methylpropane has the lowest boiling point and is the least soluble in water.

-2-butanol has a higher boiling point than -2-methylpropane, but lower than -2-pentanol and -2-propanol

-2-pentanol has a higher boiling point than -2-butanol and -2-methylpropane, but lower than -2-propanol

-2-propanol has the highest boiling point and is the most soluble in water.

Please note that this is a general trend and there can be variations depending on factors such as pressure, purity of the substance, and temperature.

Answer:

So the new concentration of the solution is 0.0001M

Explanation:

To dilute a solution by three orders of magnitude, we need to add 3 zeroes, that is 10^3 times the original volume.

The new concentration would be 0.1M / (10^3) = 0.0001M (4 sig figs)

So the new concentration of the solution is 0.0001M

Answer:

the flesh decay

but their bone remains

First group metals forms 1:1 compounds with 17th group or group 7 A. Thus, the statement is true. Aluminum forms its oxides by 2 Al and 3 oxygen atoms. Hence, the statement is false.

Ionic bonds are formed between metals and non metals. Metals are electron rich and easily loss one or more electrons to electron deficient nonmetals.

First group elements are called alkali metals. They have one valance electron. Group 7A are halogens  with 7 valence electrons. They need one more electron to achieve octet.

Thus, alkali metals donate their valence electron to halogens and forms 1:1 compound. Therefore, the statement is true.

Aluminum reacts with oxygen to form its oxide Al₂O₃. Thus, 2 Al and 3 Os are  combined to form covalent bond. Thus, the statement is false.

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Answer:

Explanation:

The equivalent mass of the metal can be calculated using the following equation:

Equivalent Mass = (3.15 g Nitrate)/(1.35 g Metal Oxide) * (1 mole Nitrate)/(1 mole Metal Oxide)

Using the molar masses of nitrate (NO3) and metal oxide (MO):

Equivalent Mass = (3.15 g NO3)/(1.35 g MO) * (1 mol NO3)/(1 mol MO)

= (3.15 g NO3)/(1.35 g MO) * (62.00 g NO3)/(molar mass of MO)

The molar mass of the metal oxide (MO) must be known to calculate the equivalent mass of the metal.

The volume of the gold plates in cm₃ is 2.513274 cm₃

Volume is the space occupied by a three-dimensional object“”

Volume = {mass} {density}

Given that the thickness or height of medallion, h = 2 mm = 0.2 cm

Diameter of the medallion, d = 4 cm

Radius of medallion, r = d/2 = 2 cm⁻³

The thickness of the gold plating, x = 1 μm = 10⁻⁴ cm

The density of gold = 19.3 g cm

Now we know that the shape of a medallion is cylindrical.

Hence, the volume of the medallion before platting,

Vbefore = π.r2.h = π.(2)2.0.2 = 2.513274 cm₃

Therefore, the volume of the gold-plated is 2.513274 cm₃.

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Chemical reactions that release heat energy are called exothermic reactions. example:

C(g)+O2(g)→CO2(g)+thermal energy. A chemical reaction that absorbs heat energy is called an endothermic reaction. example:

CaCO3Heat→CaO+CO2.

A chemical reaction or physical change is endothermic when the system absorbs heat from the environment. In an endothermic process, the system gains heat from the environment and reduces the temperature of the environment.

A chemical reaction that releases energy is called exothermic. In an exothermic reaction, more energy is released in forming bonds within the products than is expended in breaking bonds within the reactants. Chemical reactions that absorb (or consume) energy are called endothermic.

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Answer:

CH3NH3Pbl3

Explanation:

is an example of a perovskite th that would be used in a perovskite solar cell

Holide Perovskite