Which phase change is exothermic?

Answer:

o diferença chave entre a radioatividade e a transmutação é que a radioatividade se refere à transmutação natural, enquanto a transmutação se refere à mudança de um elemento químico em outro por meios naturais ou artciais.Tanto a radioatividade quanto a transmutação são processos químicos que envolvem a mudança de núcleos atômicos para formar um novo elemento químico a partir de um elemento químico existente. A radioatividade é um tipo de processo de transmutação

Explanation:

mais informação em; ahttps://pt.strephonsays.com/radioactivity-and-transmutation-9500

Explanation:

(I only know this thing vaguely lol)

1.) It's the study of the chemistry that is happening here on earth that is not bounded by a laboratory.

2.) The early gas clouds compressed and formed a star we now call the sun and the massive gravitational pull of this star grabbed nearby debris and the debris formed and compressed into the planets and moons that we know today.

Answer:

[tex]M_{base}=0.173M[/tex]

Explanation:

Hello there!

In this case, since the titration of acids like KHP with bases like NaOH are performed in a 1:1 mole ratio, it is possible for us to know that their moles are the same at the equivalence point, and the concentration, volume and moles are related as follows:

[tex]n_{acid}=M_{base}V_{base}[/tex]

Thus, by solving for the volume of the base as NaOH, we obtain:

[tex]M_{base}=\frac{n_{acid}}{V_{base}} \\\\M_{base}=\frac{0.8675g*\frac{1mol}{204.22g} }{0.02456L} \\\\M_{base}=0.173M[/tex]

Best regards!

Answer:

[tex]k =0.101 \ min^{-1}[/tex]

Explanation:

From the given information:

The initial concentration of a chemical [tex]C_{AO} = 15 \ mg/L[/tex]

The final concentration is [tex]C_A = 5 \ g/m^3[/tex] = 5 mg/L

Volume flow rate [tex]V_o = 0.42 \ m^3/sec[/tex]

Volume of the tank V = 500 000 L = 500 m³

The time t is determined by using the formula:

[tex]t= \dfrac{V}{V_o}[/tex]

[tex]t= \dfrac{500 \ m^3}{0.42 \ m^3/sec}[/tex]

t = 1190.47 sec

t ≅ 19.8 min

∴

The rate of the decay constant is:

[tex]kt= \dfrac{C_{AO}-C_{A}}{C_A} \\ \\ k = \dfrac{1}{19.8}( \dfrac{15-5}{5})[/tex]

[tex]k =0.101 \ min^{-1}[/tex]

Answer:

67.5 atm

Explanation:

To answer this problem we can use Boyle's law, which states that at constant temperature the pressure and volume of a gas can be described as:

P₁V₁=P₂V₂

In this case:

P₁ = 101.3 atm

V₁ = 0.500 L

P₂ = ?

V₂ = 0.750 L

We input the data:

101.3 atm * 0.500 L = P₂ * 0.750 L

And solve for P₂:

P₂ = 67.5 atm

Answer:

See explanation.

Explanation:

Hello there!

In this case, for the chemical reaction:

[tex]H_2O(g) CO(g)\rightleftharpoons CO_2(g) H_2(g)[/tex]

It is widely known that the the only factor altering the equilibrium constant is the temperature because of its thermodynamic definition:

[tex]K=exp(-\frac{\Delta G(T)}{RT} )[/tex]

Which is temperature dependent on the denominator and on the Gibbs free energy of reaction. In such a way, the answers can be just f and g, as the other factors modify Q (reaction quotient) rather than K. Thus, we can discuss about f and g:

f. This would increase K if the Gibbs free energy of reaction is positive (nonspontaneous).

g. This would increase K if the Gibbs free energy of reaction is negative (spontaneous).

It is important to discuss those two because the Gibbs free energy is not given.

Regards!

Answer:

9.43 L Br₂ (g)

Explanation:

First, write a balanced reaction equation. Then use dimensional analysis to convert from grams of aluminum chloride to moles of aluminum chloride (with molar mass from the periodic table), from moles of aluminum chloride to moles of bromine gas (using the balanced equation), and from moles of bromine gas to liters of bromine gas (remember at STP, 1 mol = 22.4 L). See the attached image for the work out. Finally, account for sig figs to get 9.43 L of bromine gas

Answer:

When an element exists in more than one crystalline form, those forms are called allotropes; the two most common allotropes of carbon are diamond and graphite. Every carbon atom is covalently bonded at the four corners of the tetrahedron to four other carbon atoms.

Answer:

0.31g KCl

Explanation:

Before we can start, we have to wonder, how many moles of KCl is formed from KClO3? To figure that out we have to make a balanced equation.

KClO3 -> KCl + O2

How do I know it makes O2? Looking back at the problem they're asking for KCl, which has less ions than KClO3 so it must have been broken down. So we can say it's a decomposition type of reaction. We can't just slap on O3, we know oxygen is one of our diatomic elements that usually exists as O2 so we'll put it down as O2 and balance our equation.

2KClO3 -> 2KCl + 3O2

Now that we know every 2 moles of KClO3 makes 2 moles of KCl, this is our mole to mole ratio. Knowing the ratio between the 2 compounds in our problem is the stepping stone from converting from grams KClO3 -> moles KClO3 -> moles KCl -> grams KCl.

1. Let's first convert grams KClO3 -> moles KClO3

[tex]0.500g KClO3 x \frac{1 mol}{123g KClO3} = 0.0041 mol KClO3[/tex]

2. Convert moles KClO3 -> moles of KCl using our mole to mole ratio

[tex]0.0041 mol KClO3 x \frac{2 mol KCl}{2 mol KClO3} = 0.0041 mols KCl[/tex]

3. Convert moles KCl -> grams KCl

[tex]0.0041 mol KCl x\frac{75g KCl}{1 mol} = 0.31g KCl[/tex]

Answer:

Convection

Explanation:

Convection definition:

the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.

The method of heat transfer that occurs when particles move through a fluid is called convection.

Convection relies on the principle of fluid flow, where hotter particles become less dense and rise while cooler particles sink due to their increased density.

This movement creates a continuous circulation of the fluid, enabling the transfer of thermal energy. As the hot particles rise, they carry their thermal energy with them, and as the cooler particles sink, they absorb heat from their surroundings.

Convection is also observed in natural phenomena such as ocean currents, air currents, and even the movement of magma in the Earth's mantle.

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Answer: 4.87 g

Explanation:

We know that for every 3 moles of zinc that are consumed, 3 moles of hydrogen are produced (we can reduce this to the number of moles of zinc consumed = moles of hydrogen produced)

We know that the formula mass of hydrogen is 2(1.00794)=2.01588 g/mol, so in 0.15 g, there is about 0.15/2.01588 = 0.074409191023275 moles.

This means that about 0.074409191023275 moles of zinc are needed, and since the atomic mass of zinc is 65.409 g/mol, the answer is (0.074409191023275)(65.409)=4.87 g

You take the mass of carbon dioxide, 56.8g, divide by its molar mass, 44.01g/mol, to produce the moles of carbon dioxide. This is multiplied by the molar ratio of butane/CO2, (2/8) = 1/4, which gives the moles of butane required to produce the carbon dioxide.

The mass of a substance is the product of the moles and the molar mass. 65.5 g of carbon dioxide will be able to produce 21.62 grams of butane.

The mass of a reactant or a product is estimated by the number of moles and the molar mass of the substance.

The combustion reaction of methane is shown as,

2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O

Given,

Molar mass of butane = 58.12 g/mol

Mass of carbon dioxide = 65.5 g

Molar mass of carbon dioxide = 44.01 g/mole

Moles of carbon dioxide are calculated as,

Moles = mass ÷ molar mass

= 65.5 ÷ 44.01

= 1.488 moles

From the above reaction, two moles of butane produce eight moles of carbon dioxide. So, 1.488 moles of carbon dioxide will be produced from,

2 × 1.488 ÷ 8 = 0.372 moles

The moles of butane required is 0.372 moles

The mass of butane from moles is calculated as,

Mass = moles × molar mass

= 0.372 × 58.12 g/mole

= 21.62 gms

Therefore, 21.62 gm of butane is required to produce 65.5 g of carbon dioxide.

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Answer:

N2 + 3H2 ———> 2NH3

As we know 1000 grams ammonia is 58.82 moles so according to unitary method,

2 mole NH3 formed by 1 mole N2 hence 58.82 NH3 will be given by 29.41 moles N2.

No. Of moles = given mass/molar mass

Implies that

Mass of nitrogen required = 29.41*28 = 823.48 grams.

Explanation:

Answer:

C₃H₈O

Explanation:

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

Mass of Carbon (C) = 0.599 g

Mass of Hydrogen (H) = 0.134 g

Mass of Oxygen (O) = 0.266 g

Empirical formula =?

The empirical formula of the compound can be obtained as follow:

C = 0.599 g

H = 0.134 g

O = 0.266 g

Divide by their molar mass

C = 0.599 / 12 = 0.050

H = 0.134 / 1 = 0.134

O = 0.266 / 16 = 0.017

Divide by the smallest

C = 0.050 / 0.017 = 3

H = 0.134 / 0.017 = 8

O = 0.017 / 0.017 = 1

Empirical formula => C₃H₈O

Answer:

1.2*10^24 molecules of CF4

Explanation:

the molar mass of cf4 is 88.0043 g/mol

176/88.0043 = 2 moles of CF4

Then multiply by avogadro's number (6.022*10^23) to get the number of molecules

2*6.022*10^23 = 1.2*10^24 molecules of CF4

There are 1.204 × 10²⁴ molecules of carbon tetrafluoride in 176 grams of CF4.

HOW TO CALCULATE NUMBER OF MOLECULES:

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This question is incomplete, the missing diagram is uploaded along this question below.

Answer:

Each time you are to decrease the volume by 4 mL

Explanation:

From the image, we can see that the volumes of each syringes are displayed;

the first syringe reads 22

the second  syringe reads 18

the third syringe reads 14

the fourth syringe reads 10

and the fifth syringe reads 6

Thus, if we notice the consecutive reading on the syringes, we will notice that each successive step reduces the volume by 4 mL

Therefore, Each time you are to decrease the volume by 4 mL

Answer:

74.08%

Explanation:

We'll begin by calculating the mass of

Oxygen in 4 g of N₂O₅. This can be obtained as follow:

Molar mass of N₂O₅ = (14×2) + (16×5)

= 28 + 80

= 108 g/mol

Mass of oxygen in N₂O₅ = 5 × 16 = 80 g

Mass of oxygen in 4 g of N₂O₅

= 80 / 108 × 4

= 2.963 g

Finally, we shall determine the percentage of oxygen in 4 g of N₂O₅. This can be obtained as follow:

Mass of oxygen = 2.963 g

Mass of N₂O₅ = 4 g

Percentage of oxygen =?

Percentage of oxygen = mass of oxygen / mass of N₂O₅ × 100

Percentage of oxygen = 2.963 / 4 × 100

Percentage of oxygen = 74.08%

Answer:

When you build up a soapy lather, the molecules help lift the dirt, oil and germs from your skin

Explanation:

Soap molecules have one end that bonds with water and the other end that bonds with oils and fats .

Hope this helped!!

Answer:

The type of reaction is a single-replacement reaction.

Explanation:

Mg switches places with H, leaving H by itself.

Answer:

dry ice or solid carbon(iv)oxide

Explanation:

carbon(iv)oxide that sublimes is known as dry ice or solid CO2 and it is used to refrigerate food instead of ordinary ice which will just melt when exposed to hot conditions and there4 will lead to the destruction of food. dry ice will sublime the moisture from the food there4 keeping out any moisture

Answer:

Only anions

Explanation:

Polyatomic positive ions often have common name ending with the suffix anions

Answer:

Dude its A.Feeding

Explanation:

Its common scene that when u eat you are getting nutrient directly from the food. Come on Sponge Bob Me Boy

Ans：2.3

Explanation:

pH = -log[H+(aq)]

= -log[0.00476]

=2.3

As HCl solution is monobasic. Each molecule ionizes in water to form ONE hydrogen ion. So the H+(aq) is equal to its molarity.

2.3 is he pH of a 0.00476 M HCI solution and this value tells that solution is acidic in nature.

pH of any solution can be define as the negative log of the concentration of the H⁺ ions.

In the question given that:

Concentration of HCl solution = 0.00476 M

Concentration of H⁺ ions is equal to concentration of HCl solution as it completely ionize into their ions. So, pH can be calculated as:

pH = -log[H⁺] = -log[0.00476] = 2.3

Hence, pH of the solution is 2.3.

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