A chemist is identifying an unknown solid substance that appears purple in color. Upon close inspection with a hand lens, she notices tiny grains in the substance. Some of the grains are blue; other grains are red. Based on this information, the substance is most likely a \

Answer:

D

Explanation:

If the atom is neutral, the sum of the core and valence electrons is the same as the number of protons, which is the atomic number of the element. So if the sum of the core and valence electrons in a neutral atom equals 25 , that is the number of protons in the atomic nucleus, and the atomic number of the element.

The number of valence electrons plus core electrons is the atomic number.

The variety of protons, neutrons, and electrons in an atom may be determined from a set of easy guidelines. The wide variety of protons within the nucleus of the atom is equal to the atomic quantity (Z). The quantity of electrons in an impartial atom is identical to the number of protons.

The variety of protons in a nucleus is called the atomic variety and usually equals the number of electrons in orbit approximately that nucleus (in a nonionized atom). For this reason, all atoms which have an equally wide variety of protons and the atomic range are atoms of the equal element.

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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

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:

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:

Protons, Electrons, Neutrons

Explanation:

Neutron: 0 or Neutral

Electron: -1 or Negative

Proton: +1 or Positive

For proton and neutron look at neutr for neutral and p for positive

Answer:

❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️

The answer is Protons, Electrons, Neutrons

There is three of them.....

Hope this will help you

❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️

Explanation:

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:

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:

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.

12

Explanation:

Look at the number directly after the number you want to keep. I'm your case you want to keep the first two numbers and the number directly after is 4 so there is no need to round up. Keep your 12 without a decimal.

Answer:

A

Explanation:

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

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:

Explanation:

To find [H+] in the solution we must first find the pH

That's

pH = - log[H+]

pH + pOH = 14

pOH = 0.253

pH = 14 - 0.253

pH = 13.747

Since we've found the pH we can now find the [H+] in the solution

We have

pH = - log[H+]

13.747 = - log[H+]

Take antilog of both sides

We have the final answer as

[tex][H+] = 1.79 \times {10}^{ - 14} M[/tex]

Hope this helps you

Answer:

Okay so we know that pOH + pH = 14, so if pOH is 0.253 the pH would be 13.747.  

And pH = -log [H+], so [H+] = 10^(-pH) -->This is just the antillog...  

so [H+] = 1.791e-14, which would make sense for the strongly basic solution (so B is the correct answer)  

Hope this helps...

Answer:

C.) The number after it is between 5 and 9

Explanation:

If the digit to the right is less than five, you must leave the digit you want to round to as it is.

But, if the digit to the right is greater than or equal to five, you must increase the value of the digit you're rounding to by one. And any remaining digits before the decimal point become zeros, and any that are after the decimal point are dropped.

Hope this helps you out! : )

Answer:

the mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K is

[tex]31g[/tex]

Explanation:

To determine the mass of potassium nitrate needed to

produce a saturated solution of potassium nitrate in 50 grams of water at 313 K?, then it implies that we need to determine the

solubility of KNO3 is 62g KNO3 in 100g H2O at 313K. And this simply the amount of solute that when it dissolved in that water, then the water will not be able to take more solute again which means it has been saturated.that is the maximum quantity that the water can take at 313K.

If the solubility of KNO3 is 62g KNO3 in 100g H2O at temperature 313K

Then 50 g of water contains potassium nitrate = (62/100 X 50) at 313k = 31g

Therefore, the mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K is

31g

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:

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:

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:

it would decrease [h+]

Explanation:

 This is due to  neutralization If a base is added to an acidic solution, the solution becomes less acidic and its position changes to the middle of the pH scale.

hope this helps

Answer:

Raise the pH

decrease [H+]

Explanation:

=> Adding base would raise the pH (Bases have more pH and Acids have less pH)

=> Adding base would decrease the concentration of [H+] ions as it contains hydroxyl ions which neutralized with H+ ions so as a result the concentration of [H+] ions decreases.

Answer:

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

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:

ionic

Explanation:

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:

d. [HI] > [H2]

Explanation:

The explanation at equilibrium is shown below:-

Data provided           [tex]H_2(g) + I(g) \rightleftharpoons 2HI_(g)[/tex]

Initial concentration    -           -           [tex]\frac{2.80}{10}[/tex] = 0.280 M

At equilibrium             x          x       0.280 - 2x

[tex]K_c = \frac{(HI)^2}{(H_2)(I_2)} = 62.9[/tex]

[tex]= \frac{(0.280 - 2x)^2}{x^2} = 62.9\\\\4x^2 - 1.12x + 0.0784 = 62.9x^2[/tex]

After solve the above equation we will get

x = 0.0282 M

Therefore at equilibrium

[tex][H_2] = [I_2] = x = 0.0282M\\\\[/tex]

[tex][HI] = 0.280 - 2x = 0.2236 M[/tex]

Hence, the correct option is d.

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:

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:

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%

Answer:

The correct options are;

C. Divergent plate boundary

D. Normal faults

Explanation:

Tensile stress tends to pull objects part by acting axially upon the object to pull the object on a cross section perpendicular to the objects cross-section

The most common stress in convergent plate boundaries is compression stress

The most common stress in divergent plate boundaries is tensile stress

In the presence of tensile stress, normal faults results in the raising of mountains due to their enormous forces

Therefore, the features of Earth's crust involving tension are divergent plate boundary and normal faults.

Answer:c and d

Explanation:

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:

Only characteristics that are coded for by genes can be inherited. The shape of a person's face is inherited because this characteristic is coded for by genes. Characteristics that are due to environmental factors cannot be inherited. A scar due to an injury cannot be inherited because this characteristic is a result of an environmental factor.

Explanation:

sample response

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.