1) Determine a fórmula da base hidróxido de bário: * 1 ponto a) b) c) d) 2) As bases são substâncias iônicas, ou seja, quando são solubilizadas em água liberam íons, qual das características abaixo pode ser atribuída as soluções iônicas? * 1 ponto a) Conduzem corrente elétrica. B) Isolantes elétricos. C) Radioatividade. D) Emissão de raio UVA.

Answer:

hi there

you're answer would be:

The landscape varies greatly throughout the United States due to geology and weather. Things like volcanoes, the Ice Age, floods, rain, winds and drought have made an impact on the land.

hope this answer correct

Answer:

these are two atoms which have the same number of protons but different number of neutrons

Answer:

81.6%

Explanation:

mass of acetylferrocene and ferrocene mixture = 22.092 g

mass ratio acetylferrocene and ferrocene mixture = 1 : 1

The sum of the ratios = 2, therefore the mass of each compound will be half the mass of the mixture

mass of each compound in the sample mixture = 1/2 * 22.09 2= 11.046 g

mass of recovered acetylferrocene = 9.017 g

percentage recovery = mass recovered/mass in sample * 100%

percentage recovery of acetylferrocene = (9.017 g / 11.046 g) * 100%

percentage recovery of acetylferrocene = 81.6%

Bohr describe the arrangement of particles within an atom by: O D. Protons and neutrons form the nucleus of the atom, with electrons orbiting it.

This hypothesis states that the atom's core is a small, compact, positively charged nucleus. Protons which have a positive charge and neutrons which are neutral are both found in the nucleus.

Specific energy levels or electron shells are where the negatively charged electrons orbit the nucleus. Due to the quantization of these energy levels, only a limited number of discrete energy states are accessible to electrons.

Therefore the correct option is D.

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Answer:

The equilibrium concentration of I₂ is 0.400 M  and HI is 1.20 M, the Keq will be 0.112.

Explanation:

Based on the given information, the equilibrium reaction will be,  

2HI (g) ⇔ H₂ (g) + I₂ (g)

It is given that 4.00 mol of HI was filled in a flask of 2.00 L, thus, the concentration of HI will be,  

= 4.00 mol/2.00 L

= 2.00 mol/L

Based on the reaction, the initial concentration of 2HI is 2.00, H₂ is 0 and I₂ is O. The change in the concentration of 2HI is -x, H₂ is x and I₂ is x. The equilibrium concentration of 2HI will be 0.200-x, H₂ is x and I₂ is x.  

It is given that at equilibrium, the concentration of H₂ or x is 0.400 M.  

Now the equilibrium concentration of HI will be,  

= 2.00 -2x  

= 2.00 - 2 × 0.400

= 1.20 M

The equilibrium concentration of I₂ will be,  

I₂ = x  

= 0.400 M

The equilibrium constant (Keq) will be,  

Keq = [H₂] [I₂] / [HI]²

= (0.400) (0.400) / (1.20)²

= 0.112

Thus, the Keq of the reaction will be 0.112.  

Answer:

The correct option is;

(B) 1 s², 2s², 2p⁶, 3s², 3p³

Explanation:

The electron configuration is the outline of the electron arrangement about a nucleus

In the systemic pattern of electron arrangement within an atom, there are, s, p, d, f orbitals

The maximum number of electrons in an s, p and d orbital = 2, 6, and 10 respectively

Based on Aufbau's principle the electrons are arranged based on the order of their energy level

The charge is presented by the number of electrons in the outermost shell, an element able to form an ion of charge of -3 will gain 3 electrons to complete its outermost shell

Among the options given, option B is the only option that has the capacity to take the electrons to complete the number of electrons in the p orbital outermost shell to 6 from 3, that is 3p³ + 3e⁻→ 3p⁶.

Answer:

34.79 atm.

Explanation:

The following data were obtained from the question:

Initial pressure (P1) = 12 atm

Initial temperature (T1) = 25 °C

Final temperature (T2) = 591 °C

Final pressure (P2) =...?

Note: the volume of the tank is constant.

Next, we shall convert celsius temperature to Kelvin temperature. This can be obtained as follow:

Temperature (K) = Temperature (°C) + 273

T(K) = T (°C) + 273

Initial temperature (T1) = 25 °C

Initial temperature (T1) = 25 °C + 273 = 298 K.

Final temperature (T2) = 591 °C

Final temperature (T2) = 591 °C + 273 = 864 K.

Finally, we shall determine the new pressure as follow:

Initial pressure (P1) = 12 atm

Initial temperature (T1) = 298 K.

Final temperature (T2) = 864 K.

Final pressure (P2) =...?

P1/T1 = P2/T2

12/298 = P2/864

Cross multiply

298 x P2 = 12 x 864

Divide both side by 298

P2 = (12 x 864)/298

P2 = 34.79 atm.

Therefore, the new pressure is 34.79 atm.

Answer:

3850g

Explanation:

Solubility is the amount of solute dissolved in a solvent.

Solubility is mass of solute÷mass of solvent

The solvent is 35grams

Solute?

Solubility of solute is 110

110=x/35

= 110 × 35

The amount of residue solute is 3850g

Carbon 14 would be your answer, however if it's more than one answer it would also be Carbon 12, so yeah. Your best bet would be Carbon 14.

Answer:

The initial volume of the container was 1.27L

Explanation:

Avogadro's law states that under the same pressure and temperature, equal moles of gases occupies equal volume. The equation is:

V₁n₂ = V₂n₁

Where V is volume and n moles of 1, initial state and 2, final state.

In the problem, initial moles are 5.67x10⁻², final moles after the addition are:

5.67x10⁻² + 2.95x10⁻² = 8.62x10⁻² moles

And, after the addition, the volume is 1.93L.

Replacing in Avogadro's law:

V₁×8.62x10⁻² moles = 1.93L×5.67x10⁻² moles

V₁ = 1.27L

Answer:

In this titration, solution P (that contains hydrochloric acid) is added into the conical flask that contains sodium hydroxide drop by drop. The indicator (phenolphthalein) changes color when all the NaOH is completely neutralized.

i) Solution P contains hydrochloric acid. Hydrochloric acid is the chemical that reacts with sodium hydroxide to give salt and water.

This type of reaction is called neutralization.

ii) Under alkaline conditions, phenolphthalein appears pink in color. When the solution becomes neutral or acidic, it is colorless.

So, the color change of the mixture at the end point is from pink to colorless.

iii) same explanation from question i,

HCl (aq) + NaOH (aq) --> NaCl (aq) + H2O (l)

iv) no. of moles = volume (in dm3) x concentration

hence,

no. of moles of NaOH used = 25/1000 x 0.1

= 0.0025 mol

From the equation in (iii), since the mole ratio of HCl : NaOH = 1:1, meaning 1 mole of HCl reacts completely with 1 mole of NaOH.

This also means that the no. of moles of NaOH reacted equals to the no. of moles of HCl needed to react with it, which is 0.0025 mol.

Given the concentration of HCl in solution P is 0.1 mol /dm3. (pls correct me if I misunderstood your comment),

if v is the volume of HCl needed,

0.0025 = 0.1 v

v = 0.025 dm3

also = 25 cm3

Answer:

In this titration, solution P (that contains hydrochloric acid) is added into the conical flask that contains sodium hydroxide drop by drop. The indicator (phenolphthalein) changes color when all the NaOH is completely neutralized.

i) Solution P contains hydrochloric acid. Hydrochloric acid is the chemical that reacts with sodium hydroxide to give salt and water.

This type of reaction is called neutralization.

ii) Under alkaline conditions, phenolphthalein appears pink in color. When the solution becomes neutral or acidic, it is colorless.

So, the color change of the mixture at the end point is from pink to colorless.

Explanation:

Answer:

1. Equivalence point

2. Direct titration

3. Primary standard

4. Titrand

5. Back titration

6. Standard solution

7. Titrant

8. Indirect titration

9. End point

10. Indicator

Explanation:

1. The equivalence point is the tiration point at which the quantity or moles  of the added titrant is sufficient or equal to the quantity or moles of the analyte for the neutralization of the solution of the analyte.

2. Direct titration is a method of quantitatively determining the contents of a substance

3. A primary standard is an easily weigh-able representative of the mount of moles contained in a substance

4. A titrand is the substance of unknown concentration which is to be determined

5. The titration method that uses a given amount of an excess reagent to determine the concentration of an analyte is known as back titration

6. A standard solution is a solution of accurately known concentration

7. A titrant is a solution that has a known concentration and which is titrated unto another solution to determine the concentration of the second solution

8. Indirect titration is the process of performing a titration in athe reverse order

9. The end point is the point at which the indicator indicates that the equivalent quantities of the reagents required for a complete reaction has been added

10 An indicator is a compound used to visually determine the pH of a solution.

The titration has been the neutralization reaction in which the titrand and the titrant react to form the salt and the water and help in the determination of the qualitative and quantitative properties.

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Answer:

NO! It would be in violation of the workplace regulation regarding oxygen.

Explanation:

Bulk oxygen systems convey liquified oxygen which is of geat use and importance in institutions like a nuirsing home.

Liquified oxygen is gaseos oxygen that has been condensed under high presures into liquid form. It is transported via a complex system of vaporizers, storage tanks and pipes around the facility it is needed. Liquified oxygen is oxygen- rich.

Asphalt is a petroleum derivative that is often used to in coating surfaces and tarring roads.

Its primry constituent is Carbon with minor constitunets like sulphur, nirogen, oxygen. As a petrolem derivative, it is very combustible.

In the event of an oxygen leak on an asphalt surtface, oxygen acting as an oxidizing agent can combine with asphalt in the presence of air, to cause a large fire.

Hence, asphalt surfacing in areas of oxygen leaks, would not be in compliance with the workplace regulation as it has the potential of causing a fire in the nursing home.    

Answer:

mass

Explanation:

The triple beam balance is an instrument used to measure mass very precisely.

The question is incomplete, the complete question is;

The Lewis representation above depicts a reaction between hydrogen (blue) and a main-group element from group______ (red).

In this representation, each Y atom needs ______ electron(s) to complete its octet, and gains these electrons by forming______ bond(s) with atoms of H .

There are ______ unshared electron pair(s) and _______bonding electron pair(s) in the product molecule.

The bonds in the product are _________ (Ionic or Covalent)

Answer:

1) 16

2) 2 electrons

3) 2 bonds

4) 2 unshared pairs of electrons

5) 2 bonding pairs of electrons

6) The bonds in the product are covalent

Explanation:

Group sixteen elements have six electrons on their outermost shell. These include two unshared pairs of electrons and two unpaired electrons. These two unpaired electrons can now be covalently bonded to two hydrogen atoms to give H2Y. The compound H2Y has two lone pairs and two bond pairs of electrons.

H2Y can be a general formula for all hydrides of group 16. They are all very similar in structure but gradually differ in physical and chemical properties according to the graduated variation observed down the group.

The molecule has been [tex]\rm H_2Y[/tex], where the two bonds have been formed for the sharing of 2 electrons pair between the H and Y atom.

The main group element that has the ability to form [tex]\rm H_2Y[/tex] type of structure has been Group 16.

The atom required 2 electrons to complete its octet, and in order to gain two electrons, the atom form 2 bonds with the H, resulting in [tex]\rm H_2Y[/tex].

The atom forms bond with the two H atoms, thus there has been the presence of two unshared electrons pair. The bonding electrons pair are also two in the molecule.

The bond has been formed with the sharing of the electron pair. Thus it has been a covalent bond.

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Answer:

C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O

Explanation:

Let's start by counting how many molecules we have on each side.

Reactants

C - 5

H - 12

O - 2

Products

C - 1

O - 3

H - 2

We have to balance both sides. Since we have 5 carbon atoms on the reactants side and 1 carbon atom on the products side, we'll start with that. Write 5 as the coefficient for CO₂ to balance the carbons.

C₅H₁₂ + O₂ → 5CO₂ + H₂O

Now that the carbons are balanced, let's look at the hydrogens. There's 12 on the reactants side and 2 on the products side. To balance the hydrogens, we have to write 6 as the coefficient for H₂O.

C₅H₁₂ + O₂ → 5CO₂ + 6H₂O

Now the hydrogens are balanced. All that's left to do is balance the oxygens. Let's start by counting how many atoms we have on each side.

Reactants

C - 5

H - 12

O - 2

Products

C - 5

H - 12

O - 16

So, to balance the number of atoms on both sides, write 8 as the coefficient for O₂.

C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O

Lastly, let's check to make sure everything is balanced.

Reactants

C - 5

H - 12

O - 16

Products

C - 5

O - 16

H - 12

Both sides are balanced. Therefore, the balanced chemical equation is: C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O.

Hope that helps.

Answer:

[tex]\boxed{C_{5}H_{12} + 8O_{2} -->5CO_{2} + 6H_{2}O}[/tex]

Explanation:

Part 1: Count the number of atoms on each side per element

To start, count the number of atoms per element on both sides of the equation.

Left Side

C - 5 atoms

H - 12 atoms

O - 2 atoms

Right Side

C - 1 atom

H - 2 atoms

O - 3 atoms

Part 2: Balance carbon atoms

Now, with this information, you can begin finding out how to properly balance both sides of the equation.

You need 5 carbon atoms on the left, so place a coefficient of 5 in front of the [tex]CO_{2}[/tex] product. This will balance the carbons. Do not place a coefficient in front of the [tex]C_{5}H_{12}[/tex] reactant - none are necessary!

Then, you can update your counts for your atoms.

Left Side

C - 5 atoms

H - 12 atoms

O - 2 atoms

Right Side

C - 5 atoms

H - 2 atoms

O - 11 atoms

The updated equation will look like this:

[tex]\boxed{C_{5}H_{12}+O_{2} --> 5CO_{2} + H_{2}O}[/tex]

Part 3: Balance hydrogen atoms

Now, balance the hydrogen atoms. Place a coefficient of 6 in front of the [tex]H_{2}O[/tex] product. This will balance the hydrogen atoms.

Once again, update the atom counts:

Left Side

C - 5 atoms

H - 12 atoms

O - 2 atoms

Right Side

C - 5 atoms

H - 12 atoms

O - 16 atoms

The updated equation will look like this:

[tex]\boxed{C_{5}H_{12} +O_{2}--> 5CO_{2} +6H_{2}O}[/tex]

Part 4: Balance oxygen atoms

To fully balance the equation, place a coefficient of 8 in front of the [tex]O_{2}[/tex] reactant. This will equalize the amount of oxygen atoms on both sides of the equation.

The updated equation will look like this:

[tex]\boxed{C_{5}H_{12} + 8O_{2} --> 5CO_{2} + 6H_{2}O}[/tex]

Part 5: Check the equation and atom counts

Now, update the atom counts one last time to make sure they are equal.

Left Side

C - 5 atoms

H - 12 atoms

O - 16 atoms

Right Side

C - 5 atoms

H - 12 atoms

O - 6 atoms

They are equal, so you may proceed.

Part 6: Check if reductions are necessary

If the equations coefficients can all be divided by a common divisor (i.e., 3), follow up with that step. However, any equation that has a reactant or product without a coefficient, skip this step entirely.

This equation falls into that category, so you may proceed past it.

Your final equation will look like this: [tex]\boxed{C_{5}H_{12} + 8O_{2} -->5CO_{2} + 6H_{2}O}[/tex]

Answer:

See below

Explanation:

Ammonium [tex](NH_{4}^+)[/tex] is not a molecular ion because it is just a poly-atomic ion. A molecular ion has a "negative or positive charge" as a whole but the positive charge on here is not on the whole. So, it is a poly-atomic ion and not molecular ion.

Answer:

The correct answer is 5021.25 kJ/mol octane

Explanation:

The heat absorbed by the calorimeter is given by:

heat absorbed = Ccal x ΔT

Given:

Ccal = 6.18 kJ/ºC (heat capacity of calorimeter)

ΔT= Final temperature - initial temperature = 41.5ºC-22.0ºC = 19.5ºC

We first calculate the heat absorbed:

heat absorbed = 6.18 kJ/ºC x 19.5ºC = 120.51 kJ

The change in internal energy (ΔE) is equal to the heat absorbed by the calorimeter. In order to determine ΔE in kJ/mol we have to divide the heat into the number of moles of octane (C₈H₁₈) burned in the calorimeter.

Molecular weight (C₈H₁₈) = (12 g/mol x 8) + (1 g/mol x 18) = 114 g/mol

Moles of C₈H₁₈= mass/molecular weight= (2.75 g)/(114 g/mol)= 0.024 moles

Finally, we calculate ΔE:

ΔE = heat absorbed/moles of octane = (120.51 kJ)/(0.024 mol octane) = 5021.25 kJ/mol octane

Answer:

Matter is any substance, if it is made up of only one kind of atom, then it is an element. Elements consists of atoms with the same weight and same number of protons in the nuclei.

Answer:

b. 2-4

Explanation:

Look at the slope of the line, between 0-2 and 4-6 the slope is only 10, but between 2-4 the slope is 20, so that's when the temperature is changing the fastest. In the same time it took for the water to increase by 20 degrees between 0-2 and 4-6, the temperature of the water increased by 40 degrees between 2-4 so that's when the change is the fastest.

Answer:

Electrochemical cells typically consist of two half-cells. The half-cells separate the oxidation half-reaction from the reduction half-reaction and make it possible for current to flow through an external wire.

Explanation:

Answer:

[tex]\boxed{2}[/tex]

Explanation:

Alkaline earth metals are in group 2. The number of valence electrons of elements in group 2 is 2.

2 valence electrons do the alkaline earth metals have. Therefore, option B is correct.

Alkaline earth metals are the elements in Group 2 of the periodic table, which includes beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).

In general, elements in Group 2 have two valence electrons. Valence electrons are the electrons located in the outermost energy level (or shell) of an atom. For the alkaline earth metals, the outermost energy level is the second energy level, which can hold up to 8 electrons.

Only the two electrons in the s sublevel of the second energy level are considered valence electrons. These two valence electrons are involved in chemical reactions and bonding.

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Answer:

The correct option is;

The reaction pathway for the trials is different

Explanation:

The effect of a catalyst in a chemical reaction is to increase the rate of a reaction by changing the pathway or mechanism of the reaction and/or to lower the transition state's energy thereby lowering the activation energy of the reaction

The pathway of the reaction is changed by the catalyst by the formation of intermediate compounds by the catalyst which require lower activation energy to form the products than the original non-catalyzed reactants. In the process the catalyst is regenerated, thereby, not taking part in the reaction.

Answer:

B) They will react because X and Y can share two pairs of electrons to become stable

Explanation:

The electron configurations of two elements x and y are given :

X: 1s2 2s2 2p6

Y: 1s2 2s2 2p6 3s2 3p6

The statement that is true for both the elements is that, they both will react as they both can share two pairs of electrons to become stable.

To become stable the outermost shell or p orbital should have 8 electrons, so element X  can gain 2 atoms to become stable.

Element Y can also react as it can also share two atoms to fulfill its 3p orbital and will stable.

Hence, the correct option is "B".

Answer:

A

Explanation:

civil deals with desighning, construction work of natural or physical environment and a fits guess

Answer:

C2H4

Explanation:

cause the compound of ethylene is C2H4

Ethylene is a hydrocarbon gas with the chemical formula C₂H₄. It is a simple molecule that consists of two carbon atoms and four hydrogen atoms and is also known as ethene. The skeletal structure is CH₂=CH₂.

Ethylene is a colorless and odorless gas that is the simplest member of the olefin class of hydrocarbons, with the chemical formula C₂H₄. It is an important organic compound and is widely used in industry.

Ethylene is primarily used to produce polyethylene, which is one of the most common plastic materials in the world. It is also used as a fuel in some industrial processes, as a refrigerant, and as a precursor to other chemicals.

It is an important plant hormone and is involved in various physiological processes such as fruit ripening, senescence, and abscission. Ethylene is naturally produced by plants, but it can also be produced artificially and is commonly used in agriculture to ripen fruits and vegetables.

Thus, the ethylene compound is CH₂=CH₂.

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Answer:

s orbital

Explanation:

The orbital shown is a py orbital. py orbitals overlap side by side with s orbital to form a sigma bond. Looking at the direction of the Px and py orbitals, overlap of these with a py orbital can only lead to the formation of a pi bond.

However, the s orbital being spherically symmetric overlaps with py orbital in such a manner that a sigma bond is formed. The s orbital overlaps with one of the lobes of the py orbital.

Sigma bonds are formed by end to end overlap of atomic orbitals. It is the strongest type of covalent bond.

Answer:

chlorine is element and carbon dioxide is compound

Answer:

The correct answer would be that Chlorine is an Element and Dioxide is an Compound.

Answer:

a white precipitate of barium chloride is formed as displacement reaction takes place.

Answer:

Change in T = i x m x kf. Where i is the number of particles the compound dissociates, m is the molality, and kf is the constant specific to water.  MM of MgCl2 = 95.21 g/mol

MgCl2 will form three atoms....i = 3......1Mg + 2Cl

kf = 1.86

moles of MgCl2 = 1.43g/95.21 = 0.015

m = moles solute/ kg solvent = 0.015/.1kg = .15m

Change in T = (3)(.15)(1.86) = .838

This is the depression of the freezing point of water, it is negative because the water's new freezing point is its normal freezing point minus the change in T.

0 - .838 = -.838

Explanation: