To change an object from a liquid to a gas _________ must happen

melting
evaporation
sublimation
condensation

If the base-dissociation constant, kb, for an unknown base is the acid-dissociation constant, ka, for the conjugate ion then Ka and Kb is 1× 10^(-7).

The base dissociation constant is defined as the measurement of the ions which base can dissociate or dissolve in the aqueous solution. The greater the value of base dissociation constant greater will be its basicity and strength.

The acid dissociation constant is defined as the measurement of the ions which acid can dissociate or dissolve in the aqueous solution.The greater the value of acid dissociation constant greater will be its acidity and strength.

The correlation between base dissociation constant and acid dissociation constant are given as

Kw = Ka × Kb

where Kw = 10^(-14).

Ka is the acid dissociation constant and Kb is base dissociation constant.

Given,

Ka = Kb

Substituting the value of Ka and Kb we get

Kw = (Ka) ^2

10^(-14) = (Ka) ^2

Ka = 10^(-7)

Thus, we find that the value of Ka and Kb is 10^(-7).

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The importance of the following below in a nuclear reactor are:

This is referred to as the device which is used to start up and control a fission or fusion nuclear chain reaction or nuclear fusion reactions.

The control rod is responsible for the absorption of neutrons so that the nuclear chain reaction taking place within the reactor core can be slowed  or stopped. The containment structure help to prevent rays from getting into the environment thereby serving as a protective factor.

The moderator helps to slow down the speed of neutrons especially in those who have a very high speed thereby making it the correct choice.

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Answer:

Ver explicación

Explanation:

El método científico se refiere al patrón establecido de resolución de un problema científico. Los siguientes son pasos importantes en el método científico;

Haz una observación.

formular preguntas relevantes.

elabore una hipótesis que pueda ser probada.

Diseña un experimento.

Prueba la hipótesis usando tu diseño experimental.

Teniendo en cuenta ambos escenarios, el último caso en el que estudiantes de diferentes capacidades trabajan juntos para resolver un problema refleja mejor el método científico porque pueden hacerse preguntas entre sí y llegar a hipótesis comprobables que pueden demostrarse como verdaderas o falsas mediante experimentos.

Answer:

0.72 moles of hydrochloric acid are needed to completely react with 0.36 mol of lead.

Explanation:

The balanced  reaction is:

Pb + 2 HCl → PbCl₂ + H₂

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of reagent participate:

You can apply the following rule of three: if by stoichiometry of the reaction 1 mole of Pb reacts with 2 moles of HCl, 0.36 moles of Pb will react with how many moles of HCl?

\(amount of moles of HCl=\frac{0.36 molesof PB*2 moles of HCl}{1 mole of Pb}\)

amount of moles of HCl= 0.72 moles

0.72 moles of hydrochloric acid are needed to completely react with 0.36 mol of lead.

The moles of HCl needed to completely react with 0.36 mole of lead is 0.72 moles.

Stoichiometry of the reaction tells about the relative amount of the reactants and products present in that reaction in terms of coefficient.

Given chemical reaction is:

Pb + 2HCl → PbCl₂ + H₂

From the stoichiometry of the reaction, it is clear that:
1 mole of Pb = react with 2 moles of HCl

0.36 mole of Pb = react with 2×0.36 = 0.72 moles of HCl

Hence, the required moles of HCl is 0.72 moles.

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Answer:

Q1= C

Q2= Ice melts when heat energy causes the molecules to move faster, breaking the hydrogen bonds between molecules to form liquid water. ... This is why an ice cube melts more quickly on the outside and retains its coldness and solidity longer at the center: melting is a cooling process.

Explanation:

Mine was 1st!

Answer:

C. At first , the water was solid. Then the water was liquid

Explanation:

The water was first ice, which is a solid.

Then it was water, this is a liquid

This means it turned from solid to liquid. Making the Answer C.

Hope you learned something. :) and STAY SAFE !

Answer:

Yes.

Explanation:

Bath bombs are usually made from three key ingredients: baking soda, citric acid and cornstarch, said Frankie Wood-Black, an instructor in chemistry at Northern Oklahoma College and an experienced bath-bomb maker. Often, bath bombs also include dyes and perfumes, and sometimes they have epsom salt.

Answer: yes

Explanation:

Answer:2

Explanation:

12.5 moles of chlorine gas at STP occupies 280 liters of volume.

What is STP?

STP stands for Standard Temperature and Pressure. It is defined as a temperature of 273.15 K (0 °C or 32 °F) and a pressure of 101.325 kPa (1 atmosphere). It is often used as a reference point for measuring and comparing physical and chemical properties of gases.

At STP (Standard Temperature and Pressure), the temperature is 273.15 K (0 °C) and the pressure is 101.325 kPa (1 atm).

The molar volume of a gas at STP is 22.4 L/mol. Therefore, to find the volume of 12.5 moles of chlorine gas, we can use the following formula:

V = n x Vm

where:

V is the volume in liters

n is the number of moles

Vm is the molar volume at STP (22.4 L/mol)

Substituting the given values, we get:

V = 12.5 mol x 22.4 L/mol

V = 280 L

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The diagram shows the stages jamila uses to make zinc sulfate and the stages in the correct order include the following below:

This is referred to as a process used to separate solids from liquids or gases using a filter medium.

In the formation of zinc sulfate, the zinc is usually added to concentrated H₂SO₄ and filtered with the use of filter paper through several techniques to ensure that the filtrate is dry and concentrated.

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Answer:

B

Explanation:

In this chemical reaction, aluminum hydroxide is the base and nitric acid is the acid.

What is chemical reaction?

The reactants in this equation are not given, so it is not possible to predict the parent acid and base with certainty. However, based on the products, we can make some educated guesses.

\(Al(NO_{3})_{3}\) is an ionic compound composed of aluminum ions (\(Al_{3}^{+}\)) and nitrate ions (\(NO_{3}^{-}\)). When this compound is dissolved in water, it dissociates into its constituent ions. The presence of  \(3H_{2}O\) molecules on the product side of the equation suggests that the reaction involves a hydrated metal ion.

One possible reactant that could produce these products is aluminum hydroxide (\(Al(OH)_{3}\)), which is a common base. When \(Al(OH)_{3}\)  reacts with nitric acid (HNO3), it forms aluminum nitrate (\(Al(NO_{3})_{3}\)) and water (\(H_{2}O\)) as products.

The balanced chemical equation for this reaction would be:

\(Al(OH)_{3}\) + \(3HNO_{3}\) → \(Al(NO_{3})_{3}\) + \(3H_{2}O\)

In this equation, aluminum hydroxide is the base and nitric acid is the acid.

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Complete question is: Based on the following products, the parent acid and base are nitric acid and aluminum hydroxide.

The correct choice is A) −5Δ[Br−]/Δt. The rate expressed as Δ[Br2]/Δt is proportional to -5 times the rate of change of Br−.

In the given reaction 5Br−(aq) + BrO3−(aq) + 6H+(aq) → 3Br2(aq) + 3H2O(aq), the stoichiometric coefficients provide information about the relationship between the reactants and products. To determine the rate expressed as Δ[Br2]/Δt, we need to compare it with the rate of change of the other species.

Based on the balanced equation, for every 5 moles of Br− consumed, 3 moles of Br2 are produced. Therefore, the rate of change of Br−, Δ[Br−]/Δt, is related to the rate of change of Br2, Δ[Br2]/Δt, by a factor of -5/3.

The other choices, B) −0.6Δ[Br−]/Δt, C) 3Δ[BrO3−]/Δt, and D) −Δ[H2O]/Δt, do not correspond to the correct relationship based on the stoichiometric coefficients of the reaction. Therefore, the correct answer is A) −5Δ[Br−]/Δt.

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The electron configuration of aluminum is 1s2 2s2 2p6 3s2 3p1.

1) The reaction is exothermic and heat is a product

2) The color would turn to pink.

Let us recall that an endothermic reaction is one in which the increase in the temperature of the system would drive the forward reaction. This implies that the equilibrium would shift to the right when the set up is heated. Since the color of the solution changes to blue when heated hence the reaction is exothermic.

If you removed heat by placing the solution in the ice bath, we can see that we have removed the heat thus we expect that the reverse reaction would take place and the color would change to pink.

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Nitric acid is a strong acid while the nitrate ion is a very weak base. Nitric acid is able to consume hydroxide ions. However, the nitrate ions present are unable to consume hydronium ions. As a result, the set of compounds does not form a buffer solution.

A mole is the number of entities present in a substance, such as atoms, molecules, or ions. A mole of any substance is defined as 6.0221023 molecules. Just as we use a standard value to quantify diverse things, such as 1 dozen = 12 items, we utilise the mole to quantitatively calculate the size of the tiniest creatures.

The number of atoms in 12g (0.012 kg) of 12C isotope is equal to the number of particles in 1 mole of the substance. One of the most crucial facts to remember is that the mole of a material always includes the same number of entities regardless of the substance.

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The Empirical Rule (or 68-95-99.7 Rule) applies to data that follows a normal distribution.

This means that roughly 68% of the data will fall within one standard deviation of the mean, 95% of the data will fall within two standard deviations of the mean, and 99.7% of the data will fall within three standard deviations of the mean.

This means that if you have a normal distribution, you can use the Empirical Rule to predict how much of your data will fall within certain ranges. For example, if you know the mean and standard deviation of your data, you can use the rule to approximate how many of your scores will fall within a certain range. This can be useful for understanding the spread of your data and making predictions about it.

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In the bicarbonate buffering system, carbon dioxide and water join to form carbonic acid, which dissociates into hydrogen and bicarbonate.

Bicarbonate is an excellent buffering system because this compound can bind free hydrogen ions (H+) and thus the system avoids sudden changes in the pH of a solution.

In conclusion, in the bicarbonate buffering system, carbon dioxide and water join to form carbonic acid, which dissociates into hydrogen and bicarbonate.

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The correct options for naming an ionic compound are:

The cation is named first and the anion second.

For a monatomic cation, the element name is unchanged.

For a monatomic anion, the element name is changed to end in -ide.

When naming an ionic compound, the cation (positive ion) is always named first, followed by the anion (negative ion). For monatomic cations, the element name remains the same. For example, Na^+ is simply called sodium.

On the other hand, for monatomic anions, the element name is modified to end in -ide. For example, Cl^- is named chloride. Greek prefixes are not used to indicate the number of atoms of a particular element present in ionic compounds.

Therefore, the correct options are: the cation is named first and the anion second, and for monatomic anions, the element name is changed to end in -ide.

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Answer:

C₆H₆

Explanation:

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

Empirical formula = CH

Molar mass of compound = 78 g/mol

Molecular formula =?

The formula of the compound can be obtained as follow:

Molecular formula = n × Empirical formula

Molecular formula = ₙ[CH]

n[CH] = 78

n[12 + 2] = 78

14n = 78

Divide both side by side 14

n = 78/14

n = 6

Molecular formula = ₙ[CH]

Molecular formula = ₆[CH]

Molecular formula = C₆H₆

Thus, the molecular formula of the compound is C₆H₆

Answer:

The links are: the number of circles in the electronic configuration of an element is represented in the periodic table as the period number that element is situated in. the number of electrons in the outermost shell of an element is represented in the periodic table as the group number that element is situated in.

Explanation:

Answer:

Using the combined gas law:

(P1 x V1) / T1 = (P2 x V2) / T2

where:

P1 = 34.5 psi (initial pressure)

V1 = 32.2 L (initial volume)

T1 = 27°C + 273.15 = 300.15 K (initial temperature in Kelvin)

V2 = 31.04 L (final volume)

T2 = 43°C + 273.15 = 316.15 K (final temperature in Kelvin)

Solving for P2:

(P1 x V1 x T2) / (V2 x T1) = P2

(34.5 psi x 32.2 L x 316.15 K) / (31.04 L x 300.15 K) = P2

P2 = 37.2 psi

Therefore, the new pressure in the tire is 37.2 psi when the temperature increases to 43°C and the volume decreases to 31.04 L.

In a 0.5 M solution of calcium phosphate (Ca3(PO4)2), the concentration of calcium ions (Ca2+) can be determined by considering the stoichiometry of the compound. In one formula unit of calcium phosphate, there are 3 calcium ions. Therefore, the concentration of calcium ions in this solution is 3 times the concentration of the calcium phosphate.

So, the concentration of calcium ions (Ca2+) in this 0.5 M solution is:

(3 calcium ions) × (0.5 M calcium phosphate) = 1.5 M

The concentration of calcium ions in the 0.5 M solution of calcium phosphate is 1.5 M.

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The major difference between altair and the sun is their difference in mass. They differ in classifications due to variations in age with Altairs being younger compared to The Suns' maturity as well as holding an A-type categorization accredited by elevated mass quantities surpassing those of The Suns'.

While there exist detectable disparities between Altair and the Sun's physical properties respective to each other; there exists a remarkable similarity between them concerning their fundamental building blocks- chemical elements like hydrogen, helium, oxygen, carbon and nitrogen that were developed through an occurrence called nuclear fission inside star cores.

Nuclear fusion is the process by which two or more atomic nuclei come together to form extensive nucleus resulting in massive amounts of energy generation required to power the stars.

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The electron-domain geometry of a species is the arrangement of electron domains around the central atom, whereas the molecular geometry is the arrangement of bonded atoms. Two species with the same electron-domain geometry may have different molecular geometries.

In the valence shell electron pair repulsion (VSEPR) theory, the electron-domain geometry refers to the three-dimensional arrangement of electron domains (bonding pairs and lone pairs) around the central atom. The electron-domain geometry is determined by the total number of electron domains around the central atom, regardless of whether they are bonding or non-bonding pairs.

The molecular geometry, on the other hand, refers to the arrangement of the bonded atoms around the central atom. It is determined by the number of bonding pairs and the number of lone pairs on the central atom. The molecular geometry is often used to describe the shape of a molecule.

For example, a species with four electron domains around the central atom has a tetrahedral electron-domain geometry. However, if all four electron domains are bonding pairs, the molecular geometry is also tetrahedral. If one of the electron domains is a lone pair, the molecular geometry is trigonal pyramidal.

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The mathematical expression for h is v²/(2g) which is based on conservation of energy and the correct option is option B.

The law of conservation of energy states that energy can neither be created nor be destroyed. Although, it may be transformed from one form to another.

Example, when a fruit is falling to the bottom, potential energy is getting converted into kinetic energy.

Conservation of energy implies

KEinitial = PEfinal

mv²/2 = mgh

therefore, h = v²/2g.

Thus, the ideal selection is option B.

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Answer:

Display behavior or engaging in physical combats with other males

Explanation:

The behavior that both territorial and used for courtship is engaging in physical combats with other males because the male display and engage in physical combats with other males in order to attracts females as their mating partner or for courtship and also the male do this so as to secure their territories from Intruders and others taking over their own found territories. This normally occur in male lizards. The male like lizards have variants color on their skin, they display to attracts females and also to secure their territory.

Answer:

94.1 %

Explanation:

We firstly determine the equation:

2H₂O + O₂ →  2H₂O₂

2 moles of water react to 1 mol of oxygen in order to produce 2 moles of oxygen peroxide.

We convert the mass of oxygen to moles:50 g . 1mol /32g = 1.56 mol

Certainly oxygen is the limiting reactant.

2 moles of water react to 1 mol of oxygen.

13 moles of water may react to 13/2 = 6.5 moles. (And we only have 1.56)

As we determine the limiting reactant we continue to the products:

1 mol of O₂ can produce 2 moles of H₂O₂

Then 1.56 moles of O₂ will produce (1.56 . 2) = 3.125 moles

We convert the moles to mass: 3.125 mol . 34 g/mol= 106.25 g

That's the 100% yield or it can be called theoretical yield.

Percent yield = (Yield produced / Theoretical yield) . 100

(100g / 106.25 g) . 100 = 94.1 %