The number of bonds an atom can form without violating the octet rule is reflected in the number of holes the "ball" for that atom has in the ball-and-stick model set. Based on that information, how many holes would you expect to see in models of atoms for each of the following elements: (4 points total; 1 point per element) a. Carbon (C)

Answer: option (a) is the correct answer

Explanation:

The complete questions says;

You observe an exothermic gaseous reaction that is not spontaneous in forward direction at 1 atm and 298K. Which of the following statements about this reaction is true? a. This reaction will become spontaneous in forward direction at some temperature below 298K. b. This reaction will be spontaneous in forward direction at a higher pressure at 298K. c. This reaction will become spontaneous in forward direction at some temperature above 298K. d. This reaction is never spontaneous. e. The reverse reaction is always spontaneous.

The Answer:

(a). This reaction will become spontaneous in forward direction at some temperature below 298K

Explanation: First of all, we can acknowledge that the reaction seen here is an exothermic one, i.e energy is released in the process outwardly and as a result temperature is reduced during this process of energy loss.

Having understood that scenario, say we reduce it's temperature by ourself than forward reaction favors and after reaching at particular temperature, therefore we can confirm this to be a spontaneous reaction.

Let us use this to confirm what we have been saying.

Given;

ΔG = ΔH - TΔS

here ΔH is negative

it is non spontaneous, which means ΔG is positive so we continuously decraeses it's temperature than at a particular temperature.

The Entropy change becomes positive and reaction becomes spontaneous and ΔG become negative.

cheers i hope this helped !!

Answer:

prepare

creates

observe

ask

records

present

Answer:

The formula of the first compound is RQ

Explanation:

Chemical formula is the simplest whole number ratio of moles of each element in the compound.

To determine the formula of a compound we must know the molar mass of each element (How many grams weighs a mole of the compound).

The formula of the second compound is RQ₃. That is 1 mole of R and 3 moles of Q.

1 mole of R weighs 7.00g. That means its molar mass is 7g/mol.

3 moles of Q weighs 4.50g. Its molar mass is 4.50g / 3 moles: 1.50g/mol

In the first compound, there are 14.0g = 2 moles of R

And 3.00g of Q = 2 moles of Q.

And you can think formula is:

R₂Q₂

But, as formula is the simplest whole number ratio,

Answer:

hex-1-ene with a hydroboration-oxidation reaction

Explanation:

In this case, we can start with the structure of 1-hexanol. In this alcohol, the "OH" is on the first carbon. Thus, the alkene that this alcohol can produce must have a double bond between carbons 1 and 2, that is, hex-1-ene.

Now, it is important to know which of the reactions we can use, hydroboration-oxidation, or oxymercuration-reduction. To decide which reaction to using, we must look again at the alcohol we want to produce. In this alcohol, the "OH" is attached to a primary carbon. Therefore, the addition of the "OH" must be made on the least substituted carbon, that is, carbon number 1.

Because of this, an anti-Markovnikov reaction (a reaction in which the "OH" is added on the less substituted carbon) must be used. The reaction, which serves us then is: hydroboration-oxidation since this reaction is anti-markovnikov.

See figure 1

I hope it helps!

Answer:

Explanation:

FeCl₂(aq) + Na₂CO₃(aq) ⇒ FeCO₃(s) + 2NaCl(aq)

complete ionic equation

Fe⁺²(aq) + 2 Cl⁻(aq) + 2 Na⁺(aq) + CO₃⁻² (aq) ⇒ FeCO₃(s)+ 2 Na⁺(aq) +2Cl⁻(aq)

Spectator ions =  Cl⁻(aq) , Na⁺(aq)

Net ionic equation

Fe⁺²(aq) + CO₃⁻² (aq) ⇒ FeCO₃(s).

The Complete ionic equation:

Fe²⁺(aq) + 2Cl⁻(aq) + 2Na⁺(aq) + CO₃²⁻(aq) → FeCO₃(s) + 2Na⁺(aq) + 2Cl⁻(aq)

ii. Spectator ions: Na⁺(aq) and Cl⁻(aq)

iii. Net ionic equation:

Fe²⁺(aq) + CO₃²⁻(aq) → FeCO₃(s)

An ionic equation is a chemical equation that shows the dissociation of all soluble ionic compounds into their respective ions in a solution. It represents the species present in their ionic form rather than as complete compounds.

In an ionic equation, only the ions involved in the chemical reaction are shown, while the spectator ions, which do not participate in the reaction, are omitted. This type of equation provides a more focused representation of the chemical reaction occurring between the ions.

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Answer:

1.86 m

Explanation:

Step 1: Calculate the mass of solute and solvent in 100 grams of solution

We have a 15.0% by mass solution of MgCl₂ (solute) in H₂O (water). In 100 g of solution, there are 15.0 g of solute and 100.0 g - 15.0 g = 85.0 g of solvent.

Step 2: Calculate the moles corresponding to 15.0 g of MgCl₂

The molar mass of MgCl₂ is 95.21 g/mol.

[tex]15.0g \times \frac{1mol}{95.21 g} = 0.158mol[/tex]

Step 3: Convert the mass of water to kilograms

We will use the relationship 1 kg = 1,000 g.

[tex]85.0g \times \frac{1kg}{1,000g} = 0.0850kg[/tex]

Step 4: Calculate the molality of the solution

[tex]m = \frac{0.158mol}{0.0850kg} = 1.86m[/tex]

The molality is 1.86 m.

Given:

Mass solution of MgCl₂ in H₂O= 15%

Density= 1.127g/mL

To find:

Molality=?

Let's solve this question step by step:

Step 1: Calculate the mass of solute and solvent in 100 grams of solution

As it is given that 15.0% by mass solution of MgCl₂ (solute) in H₂O (water).

In 100 g of solution, there are 15.0 g of solute and 100.0 g - 15.0 g = 85.0 g of solvent.

Step 2: Calculate the moles corresponding to 15.0 g of MgCl₂

The molar mass of MgCl₂ is 95.21 g/mol.

Number of moles is given mass divided by the molar mass.

[tex]\text{Number of moles}= \frac{15g}{95.21g/mol} =0.158mol[/tex]

Step 3: Convert the mass of water to kilograms.

As we know, 1 kg = 1,000 g.

[tex]=\frac{85}{1000} =0.085kg[/tex]

Step 4: Calculate the molality of the solution.

Molality is a measure of the number of moles of solute in a solution corresponding to 1 kg or 1000 g of solvent.

[tex]\text{Molality}=\frac{0.158\text{mol}}{0.085\tetx{kg}} =1.86 m[/tex]

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Answer:

The percentage of ethylene glycol that is fatal is 0.15 %

Explanation:

If the toxic quantity of ethylene glycol in a 1kg or 1000 g body weight is 1.5 g then the percentage of ethylene glycol that is fatal is

[tex]\frac{1.5}{1000}[/tex] ˣ 100 = 0.15%

Hence, the percentage of ethylene glycol that is toxic for any body weight is 0.15%. This percentage is very important in various aspects of science including drug discovery and food production/processing

Answer:

Van't Hoff factor for AlCl₃ = 3 (Approx)

Explanation:

Given:

Number of observed particular = 1.79 M

Number of theoretical particular = 0.56 M

Find:

Van't Hoff factor for AlCl₃

Computation:

Van't Hoff factor for AlCl₃ = Number of observed particular / Number of theoretical particular

Van't Hoff factor for AlCl₃ = 1.79 M / 0.56 M

Van't Hoff factor for AlCl₃ = 3.19

Van't Hoff factor for AlCl₃ = 3 (Approx)

The Van't Hoff factor for the AlCl₃ solution is 3

Van't Hoff factor describes the number of ions in a solution. The Van't Hoff factor for non-electrolyte is always 1 while it varies for ionic solutions.

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

Van't Hoff factor = Actual molarity / Theoretical molarity

Van't Hoff factor for AlCl₃ = 1.79  / 0.56

Van't Hoff factor for AlCl₃ ≈ 3

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Answer:

Explanation:

To find the number of moles we must first find the molar mass of LiCL

From the question

mass = 0.550g

M(Li) = 6 Cl = 35.5

Molar mass of LiCL = 6 + 35.5 = 41.5 g/mol

Then we use the formula

[tex]n = \frac{m}{M} [/tex]

where

n is the number of miles

m is the mass

M is the molar mass

So we have

[tex]n = \frac{0.550}{41.5} [/tex]

We have the final answer as

Hope this helps you

Answer:

an element is a atom like titanium and a compound is like a water, glucose, alcohol and salt

Explanation:

the titanium is a element and water, glucose, alcohol, and salt those are a compound

Answer:

Mars

Explanation:

Mars is the planet with features that are really similar to the earth. As a matter of fact, Mars and the earth are referred to as "twin planets".

Mars and Earth are believed to have historically had even more similar attributes, however, that of mars was lost due to changes in the solar system.

The two planets are mostly similar because of their relatively similar size and proximity to the sun.

Answer:

HI!!

Explanation:

The correct answer is A) they both must decide how to allocate resources. Based on the lesson, individuals and economies are similar because both must decide how to allocate resources.

Answer:

A - They both must decide how to allocate resources

Explanation:

>.<

Answer:

solids, liquids, gases, or plasma

Explanation:

In chemistry, a chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components without breaking chemical bonds. Chemical substances can be solids, liquids, gases, or plasma

Answer:

Kinetic Molecular theory of matter

Explanation:

Answer:

The kinetic molecular theory of matter offers a description of the microscopic properties of atoms (or molecules) and their interactions, leading to observable macroscopic properties (such as pressure, volume, temperature).

Explanation:

Answer:

Below

Explanation:

The coefficients in a chemical reaction are called stochiometric coefficients

they represent the number of atoms or molecules they are multiplied to.

A chemical reaction has generally this form:

Answer:

Products to reactants

Answer:

82.5 metres

Explanation:

speed=330m|s

initial time taken =0.5÷2=0.25

distance=speed×time

330m|s × 0.25s = 82.5m

Answer:

It's 10 cenimeters per second

Answer:

1000 µL; 10 µL  

Explanation:

A p1000 micropipet is set to dispense 1000 µL.

A p10 micropipet set to dispense 10 µL.

Answer:

If you are thinking of the thermodynamic definitions Internal energy change is defined as the heat gained by a system less the work done by the system

E = Q-W. This combination is a state function meaning it depends on the initial and final states of a system and is path independent while work and heat change are path dependent.

Enthalpy change is defined as H = E+ PV A change in Enthalpy is also a state function. The most useful factor of enthalpy is that at constant pressure The heat of reaction Q is a measure of enthalpy and is also a state function.

hope this helps !!

Answer:

3.

Explanation:

Hello,

In this case, considering the given number:

[tex]2.30x10^5[/tex]

We can see that it does not have zeros to left of the first nonzero digit which is 2, therefore, we just have to consider the 2, 3 and 0 as significant figures because the right-handed zeros are actually considered. Hence, such measurement has 3 significant figures.

Answer:

yes

Explanation:

the number of protons in the nucleus of an atom determines the type element: the number of protons in an element is the atomic number on the periodic table (number at the top)

Each atom has characteristic number of protons present in it's nucleus which is unique for that element.

An element  is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom. Due to this reason all elements are different from one another.

Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.

The number of protons in the nucleus is the defining property of an element and is related to the atomic number.All atoms with same atomic number are atoms of same element.

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Answer:

a. See figure 1

b. See figure 2

c. Three cycles

d. Four Acetyl-CoAs

Explanation:

a. Draw the condensed structural formula for the activated form of caprylic acid

For the activation of the fatty acid, an ATP molecule is needed to bind AMP in the acid group and then an Acetyl-CoA molecule to generate the activated fatty acid. (See figure 1)

b. Indicate the α- & β-carbon atoms in caprylic acid

By definition, the alpha and beta carbons are the carbons that are in positions 2 and 3 respectively to the main carbon. In this case, the main carbon is the carbon from the acid group, therefore the alpha carbon will be carbon 2 (red arrow) and the beta carbon will be carbon 3 (blue arrow). (See figure 2).

c. State the number of β-oxidation cycles for the complete oxidation of caprylic acid.

To calculate the cycles we have to use the equation:

[tex]Number~of~cycles:\frac{n}{2}-1[/tex], where n is the amount of carbons, in this case, we have 8 carbons, so:

[tex]Number~of~cycles:\frac{8}{2}-1=3[/tex]

We will have 3 cycles. (See figure 3)

d. State the number of acetyl-CoAs from the complete oxidation of caprylic acid

In the β-oxidation metabolic cycle, we have a relationship between Acetyl-CoA produced and the number of carbons:

[tex]Number~of~Acetyl~Coas:\frac{n}{2}[/tex] if n=8 we will have:

[tex]Number~of~Acetyl~Coas:\frac{8}{2}=4~Acetyl~Coas[/tex]

We will have 4 Acetyl-CoAs.

I hope it helps!

Answer:

CH₃CH₂-CH₂CH₃

Explanation:

When an alkene, R-CH=CH-R reacts with H₂ in a Pt catalyst, the analogue alkane, R-CH₂-CH₂-R, is produced (Hydrogenation of alkenes via Pt/Pd catalyst)

Thus, the reaction of CH₃CH=CHCH₃ with H₂ under a platinum catalyst produce:

The analogue alkane

The addition of hydrogen to CH3CH=CHCH3 leads to the formation of CH3CH2CH2CH3.

An alkene is a hydrocarbon that contains a C=C double bond. An alkene undergoes addition reaction in which a molecule is added across the double bond to form a saturated hydrocarbon.

The addition of H2 to CH3CH=CHCH3 yields butane as shown in the image attached. The platinum metal serves a catalyst in the reaction.

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Answer:

B

Explanation:

The question is incomplete. Here is the complete question.

Consider the selenium atom, Se, and the bromine atom, Br.

Write out the full electron configuration fro each atom.

Se:

Br:

Calculate the Effective Nuclear Charge for each atom. Show all of your work for full credit.

Se:

Br:

Which atom is larger?

Answer and Explanation: Electron Configuration of an atom demonstrates the shape and energy of its electrons. One of the rules used for it is given by using Madelung's Rule, in which the order of increased energy of the electrons is:

1s < 2s < 2p < 3s < 3p < 4s < 4p < 5s < 6s < 4f < 5d < 6p < 7s < 5f < 6d < 7p

Atom of Selenium (Se) has 34 electrons. Its electron configuration is

Se: [tex]1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{4}[/tex]

Atom of Bromine has 35 electrons. Its electron configuration is

Br: [tex]1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{5}[/tex]

Effective Nuclear Charge ([tex]Z_{eff}[/tex])is the net positive charge experienced by an electron in a multi-electron atom. In other words, it is the net force that helds nucleus and electrons together.

It is calculated by: [tex]Z_{eff}=Z-S[/tex]

where

Z is the atomic number, i.e., number of protons of the atom

S is the nonvalence electrons, i.e., the number of electrons between the nucleus and the electron in question.

For Selenium (Se):

From the electron configuration, the valence shell is 4 with 6 valence electrons. Nonvalence electrons is the difference between valence and total electrons:

S = 34 - 6 = 28

[tex]Z_{eff}=34-28[/tex] = 6

The Effective Nuclear Charge of Se is 6

For Bromine (Br):

The valence shell, according to the configuration, is 4 and valence electrons are 7.

S = 35 - 7 = 28

[tex]Z_{eff}=35-28[/tex] = 7

The Effective Nuclear Charge fo Br is 7.

Bromine is larger than Selenium because it has bigger Effective Nuclear Charge, which means it held its electrons more loosely and, consequently, has a larger atomic radius.

Answer:

D. The side chains of D-Arg and D-Lys are not positioned to bind correctly at the active site

Explanation:

Stereospecificity is the ability to distinguish between stereoisomers of of a particular compound. L- and D- structures of compounds in living organisms are usually present in only one form due to stereospecificity. For example, naturally occuring amino acids in proteins are usually present as L-isomers.

Since enzyme are proteins, their active sites are composed of L-amino acid and they show stereospecificity in the reactions they catalyze. In their binding sites, only substrates complementary in structure can bind in order for catalysis to proceed. Therefore, only amino acids in the L- configuration are complementary to the active site of enzymes.

In the case of serine proteases, The side chains of -Arg and D-Lys will not be positioned properly for binding at the binding site of serine proteases, therefore, no catalysis will occur. On the other hand, L-Arg and L-Lys can bind to the catalytic site of serine proteases since they are complementary fits to the active site of the enzymes.

Answer:

See explanation

Explanation:

Anode;

Sn(s) ------> Sn^2+(aq) + 2e

Cathode;

Mn^2+(aq) + 2e ------> Mn(s)

The minimum voltage required to drive the reaction is the cell voltage. The cell voltage is obtained from;

E°cell= E°cathode - E°anode

E°cell= -1.19 - (-0.14)

E°cell= -1.05 V

Answer:

Traces of sodium impurity

Explanation:

Metal ions are identified by a characteristic colour imparted to flame by the metal ion solution. Various metals have various colours which they impart to a flame.

The energy of a flame is not sufficient for the excitation of electrons of Mg to a higher energy level. As a result of this, Mg do not give any color in Bunsen flame.

However, a few tinges of yellow-orange colour which is characteristic of sodium metal do appear when magnesium ions are exposed to a flame as a consequence of traces of sodium impurity in the magnesium ion solution.