Consider a culture medium on which only gram-positive organisms such as Staphylococcus aureus colonies can grow due to an elevated NaCl level. A yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the pH as a result and changing the color of a pH indicator chemical. This type

Answers

Answer 1
Selective & Differential Medium

Explanation:

Selective media allow specific types of organisms to develop, and inhibit the development of different living beings. The selectivity is cultivated in a few ways.For model, living beings that can use a given sugar are handily screened by making that sugar the main carbon source in the medium. On the other hand,selective hindrance of certain sorts of microorganisms can be accomplished by adding dyes, anti-infection agents, salts or explicit inhibitors which influence the digestion or enzyme systems of the living beingsDifferential media are utilized to separate firmly related life forms or groups of living beings. owing to the pre of specific colors or synthetic compounds in the media, the creatures will deliver trademark changes or development designs that are utilized for ID or separation. An assortment of particular and differential media are utilized in clinical, demonstrative and water contamination research facilities, and in food and dairy laboratoriesSelective media because elevated NaCI level is designed to help grow selective bacteria.differential media because the fermented sugar gives off a yellow halo which allows for differentiate between bacteria


Related Questions

The number of substrate molecules converted to product in a given unit of time by a single enzyme molecule at saturation is referred to as the: dissociation constant maximum velocity turnover number Michaelis constant

Answers

The turnover number refers to the number of substrate molecules converted to product per unit time by a single enzyme molecule at saturation. The Michaelis constant (Km) indicates substrate concentration for half-maximal enzyme activity, and the maximum velocity (Vmax) is reached when enzyme active sites are saturated.

The number of substrate molecules converted to product in a given unit of time by a single enzyme molecule at saturation is referred to as the turnover number, also known as kcat. This measure of enzymatic activity provides a direct indication of the active site's catalytic efficiency within the enzyme's turnover rate.

In contrast, the Michaelis constant (Km) represents the substrate concentration at which the enzyme achieves half of its maximum reaction rate, or Vmax/2. This constant is used to determine the enzyme's affinity for a substrate, with a low Km indicating a high affinity, and vice versa.

When an enzyme operates in an environment with a high concentration of substrate, it will eventually reach a point where every active site is saturated with substrate -- this is the maximum velocity (Vmax) of the reaction. The Vmax is dependent on both the speed of the enzyme and the total number of enzyme molecules available.

The relationship between Vmax, Km, and substrate concentration ([S]) is described by the Michaelis-Menten equation, which is fundamental in the study of enzyme kinetics.

The electron configuration of Ne is:
1s 12s 12p 3
1s 22s 22p 6
1s 22s 22p 33s 2
1s 22s 22p 5
1s 22s 22p 63s 1

Answers

The correct answer would be....

1s^2 2s^2 2p^6

Two or more than two atoms with different physical or chemical properties can not combine together to form an element. Therefore, the electronic configuration of Neon is 1s²2s²2p⁶.

What is element?

Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.

The systematic distribution of electrons in the various atomic orbitals is called its electronic configuration. The atomic number of neon is 10. The electronic configuration of neon is 1s²2s²2p⁶. 1,2,3 represents the number of shells and s and represents the orbitals. The superscripts represents the number of electrons in each orbitals.

Therefore, the electronic configuration of Neon is 1s²2s²2p⁶.

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when the temperature of a gas changes, it's volume decreases from 12 cm3 to 7 cm3 if the final temperature is measured to be 18°C what is the initial temperature in Kelvin units?

pls help :)​

Answers

Answer:

The initial temperature is 499 K

Explanation:

Step 1: Data given

initial volume = 12 cm3 = 12 mL

Final volume = 7 cm3 = 7mL

The final temperature = 18 °C = 291 K

Step 2: Calculate the initial temperature

V1/T1 = V2/T2

⇒with V1 = the initial volume = 0.012 L

⇒with T1 = the initial volume = ?

⇒with V2 = the final volume 0.007 L

⇒with T2 = The final temperature = 291 K

0.012 / T1 = 0.007 / 291

0.012/T1 = 2.4055*10^-5

T1 = 0.012/2.4055*10^-5

T1 = 499 K

The initial temperature is 499 K

A pump contains 1.5 L of air at 175 kPa. You draw back on the piston of the pump, expanding the volume until the pressure reads 45 kPa. What is the new volume of air in the pump?

Answers

Answer:

[tex]\large \boxed{\text{86.8 L}}[/tex]

Explanation:

The temperature and amount of gas are constant, so we can use Boyle’s Law.

[tex]p_{1}V_{1} = p_{2}V_{2}[/tex]

Data:

[tex]\begin{array}{rclrcl}p_{1}& =& \text{0.579 atm}\qquad & V_{1} &= & \text{150 L} \\p_{2}& =& \text{1.00 atm}\qquad & V_{2} &= & ?\\\end{array}[/tex]

Calculations:  

[tex]\begin{array}{rcl}0.579 \times 150 & =& 1.00V_{2}\\86.85 & = & 1.00V_{2}\\V_{2} & = &\dfrac{86.85}{1.00}\\\\& = &\textbf{86.8}\\\end{array}\\\text{The new volume of the gas is } \large \boxed{\textbf{86.8 L}}[/tex]

In the laboratory 6.67 g of Sr(NO3)2 is dissolved in enough water to form 0.750 L. A 0.100 L sample is withdrawn from this stock solution and titrated with a 0.0460 M solution of Na3PO4. a. What is the concentration of the Sr(NO3)2stock solution? b. Write a balanced molecular equation for the titration reaction. c. How many milliliters of the Na3PO4 solution are required to precipitate all the Sr2+ ions in the 0.100 L sample? (MM's: Sr(NO3)2 = 211.64; Na3PO4 =163.94)Name

Answers

Answer:

The answer to your question is below

Explanation:

Data

mass of Sr(NO₃)₂ = 6.67 g       Final volume = 0.750 L

Sample  0.100 L

[Na₃PO₄] = 0.046 M

a) [Sr(NO₃)₂

MM = 211.64 g

                          211.64 g ---------------------- 1 mol

                             6.67 g ---------------------- x

                             x = (6.67 x 1) / 211.64

                             x = 0.032 mol

Molarity = 0.032 / 0.75

Molarity = 0.042

b)

             3Sr(NO₃)₂  +  2Na₃PO₄  ⇒  Sr₃(PO₄)₂  +  6NaNO₃

              Reactants             Elements         Products

                    3                           Sr                      3

                    6                            N                      6

                    6                            Na                    6

                    2                            P                       2

                  24                           O                     24

c)

Calculate the moles of Sr(NO₃)₂ in 100 ml or 0.1 L

Molarity = moles / volume

Moles = Molarity x volume

Moles = 0.042 x 0.1

Moles = 0.0042

                  3 moles of Sr(NO₃)₂ --------------- 2 moles of Na₃PO₄

                  0.0042 moles of Sr(NO₃)₂ -------- x

                  x = (0.0042 x 2) / 3

                  x = 0.0028 moles of Na₃PO₄

Molarity = moles / volume

Volume = moles / Molarity

Volume = 0.0028 / 0.046

Volume = 0.060 L or 60.9 mL

The overall energy involved in the formation of CsCl from Cs(s) and Cl2(g) is −443 kJ mol−1. Given the following information: heat of sublimation for Cs is +76 kJ mol−1, bond dissociation energy for 12Cl2 is +121 kJ mol−1, Ei1 for Cs is +376 kJ mol−1, and Eea for Cl(g) is 349 kJ mol−1. what is the magnitude of the lattice energy for CsCl?

Answers

Explanation:

It is given that total energy is -443 kJ/mol and formula to calculate the lattice energy is as follows.

       Total energy = heat of sublimation + bond dissociation energies + ionization energy for Cs + EA of [tex]Cl^{-}[/tex] + lattice energy

       -443 kJ/mol = 76 + 121 + 376 - 349 + Lattice energy

   Lattice energy = (-443 - 76 -121 - 376 + 349) kJ

       Lattice energy = -667 kJ

Therefore, we can conclude that -667 kJ is the magnitude of the lattice energy for CsCl.


When dissolving a solid or liquid, as the temperature of the solvent increases, the rate of dissolution?
A. increases.
B. decreases.
C. stays the same.
D. either increases or decreases, depending upon the liquid.

Answers

Answer:A. Increases

Explanation:

Heating or an increase in temperature increases the kinetic energy of particles thereby increasing their motion and how they relate and react with one another.

Increase in the temperature of the solvent is directly proportional to the rate of dissolution. The rate of dissolution increases due to the increase in kinetic energy. This makes the solvent particles interact faster with the solute particles thereby increasing the dissolution rate.

In response to action potentials arriving along the transverse tubules, the sarcoplasmic reticulum releasesA) acetylcholine.B) sodium ions.C) potassium ions.D) calcium ions.E) hydrogen ions

Answers

Answer:

Calcium ions.

Explanation:

The generation of the action potential helps in the transfer of information to the different body parts. This potential occurs to the difference in membrane potential inside and outside of the cell.

The sarcoplasmic reticulum is the homologous to the endoplasmic reticulum of the cells. The sarcoplasmic reticulum contains calcium ions in it and releases the stored calcium ions on the generation of the action potential. This calcium ion is important for the action of the actin and myosin.

Thus, the correct answer is option (D).

Which of the answer choices correctly describes a solvent made of molecules that have areas of partial positive and negative charge?


ionizing solvent

polar solvent

true solvent

nonpolar solvent

Answers

Answer: polar solvent

Explanation:

Polarity can be said to mean, charge separation. Thus, polar solvents are solvents that have charge separation and the ability to solvate i.e dissolve ions.

A polar solvent molecule has slight electrical charge as a result of its shape. A typical and most common example is water, with an oxygen and two hydrogen atoms. The two hydrogen atoms are at an angle to the single oxygen atom. Water is the classic polar solvent. The oxygen atom tends to polarize electron density to itself.

The relative atomic mass of Chlorine is 35.45. Calculate the percentage abundance of the two isotopes of Chlorine, 35Cl and 37Cl in a sample of chlorine gas. (Total 2 marks)

Answers

Answer:

35Cl = 75.9 %

37Cl = 24.1 %

Explanation:

Step 1: Data given

The relative atomic mass of Chlorine = 35.45 amu

Mass of the isotopes:

35Cl = 34.96885269 amu

37Cl = 36.96590258 amu

Step 2: Calculate percentage abundance

35.45 = x*34.96885269 + y*36.96590258

x+y = 1  x = 1-y

35.45 = (1-y)*34.96885269 + y*36.96590258

35.45 = 34.96885269 - 34.96885269y +36.96590258y

0.48114731 = 1,99704989‬y

y = 0.241 = 24.1 %

35Cl = 34.96885269 amu = 75.9 %

37Cl = 36.96590258 amu = 24.1 %

hich of the following is TRUE? Group of answer choices A neutral solution does not contain any H3O+ or OH- A neutral solution contains [H2O] = [H3O⁺] A basic solution has [OH⁻] > [H3O⁺] An acidic solution has [H3O⁺] > [H2O] A basic solution does not contain H3O+

Answers

Answer:

a basic solution has [OH-] > [H3O+]

Calculate the pH after 0.018 mole of HCl is added to 1.00 L of each of the four solutions. (Assume that all solutions are at 25°C.) (a) 0.129 M acetic acid (HC2H3O2, Ka = 1.8 ✕ 10−5) (b) 0.129 M sodium acetate (NaC2H3O2) (c) pure H2O (d) 0.129 M HC2H3O2 and 0.129 M NaC2H3O2

Answers

Explanation:

Below are attachments containing the solution

The Na /K pump generates a membrane potential across the plasma membrane (PM) of the cell by transporting Na and K across the PM. The action of this pump results in the cell having a slightly ____________ charge inside the cell compared to the extracellular space.

Answers

Answer:

NEGATIVE CHARGE can best fill in the gap

Explanation:

The Na /K pump functions to maintain resting potential so that the cells will be kept in a state of a low concentration of sodium ions and high levels of potassium ions within the cell.

The processes of Na - K pump illustrates active transport since it moves Na+ and K+ ions against their concentration gradient. The energy required is supplied by the breakdown of ATP (adenosine triphosphate) to ADP (adenosine diphosphate). In nerve cells the pump is used to generate gradients of both sodium and potassium ions.

How does the sodium-potassium pump contribute to the net negative charge of the interior of the cell?

The sodium-potassium pump forces out three (positive) Na+ ions for every two (positive) K+ ions it pumps in, thus the cell loses a positive charge at every cycle of the pump.

Precipitation reactions and ionic equations
(look at attachment)

Answers

Answer:

Net ionic equation: 2OH⁻(aq) + Fe²⁺(aq)  → Fe(OH)₂(s)

Net ionic equation: 2K⁺(aq) + CH₃COO⁻ (aq) + 2Na⁺(aq) + S⁻²(aq)  → NO REACTION

Net ionic equation: CO₃⁻²(aq) + Pb⁺²(aq) → PbCO₃(s)

Explanation:

a. Solutions of calcium hydroxide and Iron (II) chloride are mixed:

We identify the reactants:

Ca(OH)₂ , FeCl₂

In excess, the Fe(OH)₂ can make precipitate

Salts from chlorides with elements from group II are soluble.

The reaction is: Ca(OH)₂(aq) + FeCl₂(aq) →  Fe(OH)₂(s)  +  CaCl₂(aq)

Ca(OH)₂(aq) + FeCl₂(aq) →  Fe(OH)₂(s)  +  CaCl₂(aq)

We dissociate the compounds, except for the solid

Ca²⁺(aq) + 2OH⁻(aq) + Fe²⁺(aq) + 2Cl⁻(aq)  →  Fe(OH)₂(s) + Ca²⁺ + 2Cl⁻(aq)

Net ionic equation: 2OH⁻(aq) + Fe²⁺(aq) → Fe(OH)₂(s)

b. Solutions of potassium acetate and sodium sulfide are mixed:

The reactants are: KCH₃COOH and Na₂S

In this case there are no precipitates, because all the salts are soluble

We make the complete reaction:

2KCH₃COO (aq) + Na₂S(aq)  → K₂S(aq) + 2NaCH₃COO (aq)

Net ionic equation is:

2K⁺(aq) + CH₃COO⁻ (aq) + 2Na⁺(aq) + S⁻²(aq)  → 2K⁺(aq) + S⁻²(aq) + 2Na⁺(aq) + CH₃COO⁻ (aq)

c. Solutions of ammonium carbonate and lead(II) nitrate are mixed:

In this case, the reactants are: (NH₄)₂CO₃ and Pb(NO₃)₂

All salts from nitrate are soluble.

Carbonate makes a precipitate when it bonds Pb.

The complete reaction is:

(NH₄)₂CO₃(aq) + Pb(NO₃)₂(aq) → PbCO₃(s) + 2NH₄NO₃(aq)

We dissociate all of the compounds, except for the solid in order to make the net ionic equation:

2NH₄⁺(aq) +CO₃⁻²(aq) + Pb⁺²(aq) +2NO₃⁻(aq) → PbCO₃(s) + 2NH₄⁺ (aq) + 2NO₃⁻(aq)

The net ionic equation is: CO₃⁻²(aq) + Pb⁺²(aq) → PbCO₃(s)

The ions that are repeated, are called spectators ions. We all cancel them.

In CF4 and NF3, the ___electron groups on the central C and N atoms have a ___ arrangement. The shapes of the molecules are determined by the number of ___ of electrons: since CF4 has ___ bonded atom(s) and ___ lone pair(s) of electrons, the shape is ___. Since NF3 has ___ bonded atom(s) and ___ lone pair(s) of electrons, the shape is ___.

Answers

Answer:

Explanation:

In CF4 and NF3, the valence electron groups on the central C and N atoms have a tetrahedral arrangement. The shapes of the molecules are determined by the number of bonding and nonbonding of electrons: since CF4 has four bonded atom(s) and zero lone pair(s) of electrons, the shape is tetrahedral.

Final answer:

CF4 and NF3 have electron groups which are arranged tetrahedrally. CF4, having four bonded atoms and no lone pairs, has a tetrahedral shape. NF3, having three bonded atoms and a lone pair of electrons, has a trigonal pyramidal shape.

Explanation:

In CF4 (Carbon Tetrafluoride) and NF3 (Nitrogen Trifluoride), the electron groups on the central carbon (C) and nitrogen (N) atoms have a tetrahedral arrangement. The shapes of these molecules are determined by the number of lone pairs of electrons.

In CF4, there are four bonded atoms and no lone pair of electrons, thus, the shape is tetrahedral. On the other hand, in NF3, nitrogen is bonded to three fluorine atoms and has one lone pair of electrons, so it has a trigonal pyramidal shape.

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When we think about the carbon cycle and human activities, it is important to differentiate between facts and hypotheses. Which of the following is NOT a fact, but is a hypothesis? A. The amount of carbon dioxide in the atmosphere has increased since 1950. B. Increasing atmospheric carbon dioxide will cause mean global temperature to increase by 2 degrees Celsius over the next century. C. The burning of fossil fuels contributes substantially to the ongoing rise of atmospheric CO2. D. In the past, atmospheric CO2 levels reached levels higher than those observed today.

Answers

Answer:

B. Increasing atmospheric carbon dioxide will cause mean global temperature to increase by 2 degrees Celsius over the next century.

Explanation:

By definition, a hypothesis is a tentative statement or prediction with little or no experimental test. Hypotheses are always formulated such that they can be rejected if experimental findings are against them.

Hypotheses are predictive and as such, the tone is often in future tense.

From the available options, only option B sound predictive of what might happen in the future.

Hence, the correct option is B.

Whch compounds is most reactive toward nucleophilic acyl substitution?

Answers

Answer:

There are five main types of acyl derivatives. Acid halides are the most reactive towards nucleophiles, followed by anhydrides, esters, and amides. Carboxylate ions are essentially unreactive towards nucleophilic substitution, since they possess no leaving group

The volume of a sample of chlorine gas is 8.00 liters at 45.0 degrees Celsius and 0.966 atm. How many moles of chlorine are present in the sample? R = 0.0821 (atm)(L)(mol-1)(K-1)

Answers

Answer:

Number of moles of Cl₂ = 0.3 mol

Explanation:

Given data:

Number of moles of Cl₂ = ?

Pressure = 0.966 atm

Volume = 8.00 L

Temperature = 45°C

Solution:

The given problem will be solve by using general gas equation, which is,

PV = nRT

R = general gas constant (0.0821 atm.L/mol.K)

Now we will convert the °C into K.

Temperature = 45+ 273 = 318 K

Now we will put the values in formula.

n = PV/RT

n = 0.966 atm × 8.00 L / 318 K ×0.0821 atm.L/mol.K

n = 7.728/26.1078 /mol

n = 0.3 mol

HELP ASAP!!!!!!! PLEASE!!!!!!!!
The relationship between electricity and magnetism is called
a. current.
b. electromagnetism.
c. a solenoid.
d. voltage.

Answers

Answer:

b

Explanation:

The equation shows a --the breaking and forming of chemical bonds that leads to a change in the composition of matter. 2. In the equation, CO2 is a . 3. In the equation, C6H12O6 is a . 4. In O2, the type of bond that holds the two oxygen atoms together is a . 5. In H2O, the type of bond that holds one of the hydrogen atoms to the oxygen atom is a . 6. The number of oxygen atoms on the left side of the equation is the number of oxygen atoms on the right side.

Answers

A chemical equation is said to be balanced if the quantity of each type of atom in the reaction is the same on both the reactant and product sides. In a balanced chemical equation, the mass and the charge are both equal. Here the given equation is C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O.

This means that new products are formed due to the change in the chemical composition of the reactants.

Hence, the equation shows a chemical reaction - the breaking and forming of chemical bonds that leads to a change in the composition of matter.

1. The equation is C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O.

2. And, in the given equation CO₂ is a product.

3. In the equation, C₆H₁₂O₆ is a reactant.

4. In O₂, the type of bond that holds the two oxygen atoms together is a non-polar covalent bond.

5. In H₂O, the type of bond that holds one of the hydrogen atoms to the oxygen atom is a polar covalent bond.

6. The number of oxygen atoms on the left side of the equation is equal to the number of oxygen atoms on the right side.

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Choose whether the statements about oil sands are true or false. The viscosity of bitumen is about 100 times greater than the viscosity of water. Oil from oil sand deposits is only obtained by first heating the sands at high temperatures. Oil sands contain sand, water, and light crude oil.

Answers

The First 2 statements stated above were false whereas the third one is a true statement.

Explanation:

The viscosity of bitumen is about 100 times greater than the viscosity of water - False

Reason - The viscosity of bitumen is about not 100 times greater than the viscosity of water, it is actually 100, 000 times greater.

Oil from oil sand deposits is only obtained by first heating the sands at high temperatures is False.

Reason- Oil from oil sand deposits is not obtained by first heating the sands at high temperatures but by using steams

Oil sands contain sand, water, and light crude oil is true.

Identify the number of bonding pairs and lone pairs of electrons in carbon dioxide. a) 2 bonding pairs and 4 lone pair b) 4 bonding pairs and 2 lone pairs c) 4 bonding pairs and 4 lone pairs d) 2 bonding pairs and 2 lone pairs e) 4 bonding pairs and 1 lone pair

Answers

Final answer:

Carbon dioxide (CO₂) consists of two oxygen atoms bonded to a central carbon atom. Each oxygen atom forms a double bond with the carbon atom. The double bond consists of two bonding pairs of electrons. Therefore, carbon dioxide has 2 bonding pairs and 0 lone pairs of electrons.

Explanation:

Carbon dioxide (CO₂) consists of two oxygen atoms bonded to a central carbon atom. Each oxygen atom forms a double bond with the carbon atom. The double bond consists of two bonding pairs of electrons. Therefore, carbon dioxide has 2 bonding pairs and 0 lone pairs of electrons. The correct option is d) 2 bonding pairs and 2 lone pairs.

The correct option is b. 4 bonding pairs and 2 lone pairs.

To determine the number of bonding pairs and lone pairs in carbon dioxide (CO2), we need to consider the Lewis structure of the molecule. Carbon dioxide has a total of 16 valence electrons, 4 from the carbon atom and 6 from each of the two oxygen atoms.

 In the Lewis structure of CO2, the carbon atom is double-bonded to each oxygen atom. Each double bond consists of one sigma (σ) bond and one pi (Ï€) bond. Since there are two double bonds, there are a total of 4 bonding pairs of electrons (2 sigma bonds and 2 pi bonds).

The Lewis structure of CO2 is as follows:

O=C=O

 Here, the carbon atom has no lone pairs, as it forms double bonds with both oxygen atoms. Each oxygen atom has 2 lone pairs of electrons, but since we are asked about the entire CO2 molecule, we consider the lone pairs on both oxygen atoms together. Therefore, there are 2 lone pairs in total for the CO2 molecule.

 In summary, carbon dioxide has 4 bonding pairs of electrons (from the 2 double bonds) and 2 lone pairs of electrons (1 on each oxygen atom). This matches option b.

A wooden object from a prehistoric site has a carbon-14 activity of 10 cpm compared to 40 cpm for new wood. If carbon-14 has a half-life of 5730 yr, what is the age of the wood?

Answers

Answer:

The answer to your question is 11460 years

Explanation:

Data

Carbon-14 activity  10 cpm

half-life = 5730 yr

Real carbon-14 activity 40 cpm

Process

1.- Write a chart to solve this problem

                    Real carbon-14      40 cpm       Time  0 years

                    After a half-life      20 cpm        Time  5730 years

                    After a half-life      10 cpm        Time 5730 years

    Total time                                                            11460 years          

2.- Conclusion

The wooden object is 11460 years old.                    

A metal object with mass of 23.2 g 23.2 g is heated to 97.0 °C 97.0 °C and then transferred to an insulated container containing 90.0 g 90.0 g of water at 20.5 °C. 20.5 °C. The water temperature rises and the temperature of the metal object falls until they both reach the same final temperature of 22.6 °C. 22.6 °C. What is the specific heat of this metal object? Assume that all the heat lost by the metal object is absorbed by the water.

Answers

Answer:

The specific heat of the object [tex]C_{obj}[/tex] = 0.457 [tex]\frac{KJ}{kg K}[/tex]

Explanation:

Mass of the object [tex]m_{obj}[/tex] = 23.2 gm

Initial temperature [tex]T_{obj}[/tex] = 97 ° c

Mass of the water [tex]m_{w}[/tex] = 90 gm

Initial temperature of water [tex]T_{w}[/tex] = 20.5 ° c

Final temperature of both water & object [tex]T_{f}[/tex] = 22.6 ° c

It is given that heat lost by the object = heat gain by the water

⇒ [tex]m_{obj}[/tex] [tex]C_{obj}[/tex] ( [tex]T_{obj}[/tex] - [tex]T_{f}[/tex] ) =  [tex]m_{w}[/tex] [tex]C_{w}[/tex] ( [tex]T_{f}[/tex] - [tex]T_{w}[/tex])

Put all the values in above formula we get

⇒ 23.2 × [tex]C_{obj}[/tex] ( 97 - 22.6 ) = 90 × 4.18 × ( 22.6 - 20.5 )

[tex]C_{obj}[/tex] = 0.457 [tex]\frac{KJ}{kg K}[/tex]

This is the specific heat of the object.

What mass (g) of barium iodide is contained in 188 ml of a barium iodide solution that has an iodide ion concentration of 0.532m 19.6 39.1 19,600 39,100 276

Answers

Final answer:

The mass of barium iodide in 188 ml of a 0.532M solution is calculated to be approximately 39.11 grams using concepts of molarity, moles, and molar mass.

Explanation:

The question is asking to find out the mass of barium iodide in a solution, given a certain volume and a concentration. The question is a standard calculation involving molarity and volume. Molarity (M) is defined as the number of moles of solute per liter of solution. Therefore, you can calculate the number of moles of solute first using the formula M = n/V, where n is the number of moles and V is the volume in liters. We can convert 188 mL to liters (0.188 L) and we know the molarity is 0.532M, so the number of moles in the solution is 0.532M * 0.188 L = 0.10 moles of iodide ions. To find the mass of barium iodide, we multiply this number by the molar mass of barium iodide, which is roughly 391.136 g/mol (from barium's molar mass of 137.327 g/mol and iodine's molar mass of 253.809 g/mol). Thus, the mass of barium iodide is 0.10 moles * 391.136 g/mol = 39.11 g.

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The carbocation electrophile in a friedel-crafts reaction can be generated in ways other than by reaction of an alkyl chloride with alcl3.give an example

Answers

Answer: iron (II) Chloride can be used instead of AlCl3

Explanation:

Friedel–Crafts alkylation reaction involves the introduction of alkyl group in  an aromatic ring with an alkyl halide using a strong Lewis acid, such as aluminium chloride, ferric chloride, or other MXn reagent, as catalyst.

The function of AlCl3​ or fecl3 in Friedel-Craft reaction, is to produce electrophile, which later adds to benzene ring. This electrophilic aromatic substitution allows the synthesis of monoacylated products from the reaction between arenes and acyl chlorides or anhydrides. The products are deactivated and do not undergo a second substitution. Normally, a stoichiometric amount of the Lewis acid catalyst is required for both the substrate and the product form complexes.

AlCl3​ or fecl3 (and other Lewis acids like it) will coordinate to halogens, and facilitate the breaking of these bonds. In doing so, it increases the electrophilic nature of its binding partner, making it much more reactive as to complete the reaction.

In a research project, a scientist adds 0.1 mole of HCN, 0.1 mole of H3O , and 0.1mole of CN- to water to make a total volume of 1 L. Will this reaction proceed to a greater extent in the forward direction or in the reverse direction

Answers

Answer:

Reverse; since the value of Q is greater than the value of K

Explanation:

The equation for the reaction can be expressed as:

[tex]HCN + H_2 O[/tex]     ⇄    [tex]H_3O^+ +CN^{-}[/tex]                [tex]k_a = 6.2 * 10^ {-10[/tex]

[tex]Q = \frac{[H_3O^+][CN^-]}{[HCN]}[/tex]  

[tex]Q = \frac{(0.1)(0.1)}{(0.1)}[/tex]

Q = 0.1

[tex]k_a = 6.2 * 10^ {-10[/tex]

Q > [tex]K_{a}[/tex]

If the value of Q is greater than [tex]K_{a}[/tex] Value; the reaction will definitely shift to reverse direction.

Gerald's science teacher mixed room temperature samples of hydrochloric acid and sodium hydroxide in a large beaker. The solution still looked clear like water, but when the students carefully touched the beaker one at a time, it felt warm to the touch.

Answers

Answer:

A.

A chemical reaction was producing a new substance.

Explanation:

Equation of the reaction

NaOH + HCl --> NaCl + H2O

Heat of neutralization is the amount of heat evolved when one mole of acid reacts with one mole of an alkaline to form one mole of water.

When a neutralisation reaction is carried out, there is an exothermic change; energy released into the surroundings therefore since heat is given out which is what is felt.

The pressure of a gas changes from 120kPa to 50kPa. The volume changes from 45L to 40L. If the initial temperature is 81°C, what is the final temperature in Kelvin units?​

Answers

Answer:

The final temperature is 131 K

Explanation:

Step 1: Data given

The initial pressure = 120 kPa = 1.18431 atm

The final pressure = 50 kPa = 0.493462 atm

The initial volume = 45 L

The final volume = 40 L

The initial temperature = 81 °C = 354 K

Step 2: Calculate the final temperature

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

⇒with P1 = the initial pressure = 1.18431 atm

⇒with V1 = the initial volume = 45 L

⇒with T1 = the initial temperature = 354 K

⇒with P2 = the final pressure = 0.493462 atm

⇒with V2 = the final volume = 40 L

⇒with T2 = the final temperature = ?

(1.18431 * 45)/354 = (0.493462*40)/T2

0.15054788 = 19.73848/T2

T2 = 19.73848/0.15054788

T2 = 131 K

The final temperature is 131 K

Final answer:

To determine the final temperature of a gas with given initial and final pressures and volumes, one applies the combined gas law. After converting the initial Celsius temperature to Kelvin, the final temperature is calculated to be 262.33K.

Explanation:

The problem at hand involves the application of the combined gas law, which allows us to calculate changes in a gas's condition. This law is represented as (P1 * V1) / T1 = (P2 * V2) / T2, where P stands for pressure, V for volume, and T for temperature in Kelvin. Given that the pressure of a gas changes from 120kPa to 50kPa and its volume changes from 45L to 40L, with an initial temperature of 81°C (which is 354.15K), we can find the final temperature.

To solve, we start with the conversion of temperatures to Kelvin and then apply the formula. The rearranged formula to find the final temperature (T2) is T2 = ((P2 * V2) * T1) / (P1 * V1). By substituting the given values, T2 = ((50kPa * 40L) * 354.15K) / (120kPa * 45L), we get a final temperature of 262.33K.

Regarding the formula Al203 which of the following is accurate

Answers

Answer:

D. The subscript 2 indicates that two atoms of aluminum are present in the substance.

Explanation:

The answer choices are:

A. The coefficient 3 indicates that there are a total of three atoms of oxygen present in the substance. B. The subscript 2 indicates that two atoms of oxygen are present in the substance. C. The chemical symbol Al indicates that oxygen is present in the substance. D. The subscript 2 indicates that two atoms of aluminum are present in the substance.

Solution

The correct formula is:

         [tex]Al_2O_3[/tex]

What you must know to answer this question is that the chemical formulas indicate the number of atoms of each element in the formula by placing a subscript to the right of the chemical symbol that represents the atom.

Thus, we can deal with each statement:

A. The coefficient 3 indicates that there are a total of three atoms of oxygen present in the substance.

Incorrect. 3 is not a coefficient but a subscript. Thus this option is wrong.

B. The subscript 2 indicates that two atoms of oxygen are present in the substance.

Incorrect. The subscript 2 is to the right of tha aluminum symbol, thus it does not represent the number of atoms of oxygen.

C. The chemical symbol Al indicates that oxygen is present in the substance.

Incorrect. The chemical symbol Al indicates that aluminum is present in the substance. Thus, this is wrong.

D. The subscript 2 indicates that two atoms of aluminum are present in the substance.

Correct. The subscript 2 is to the right of the symbol Al, which is the chemical symbol for aluminum. Thus, this indicates that there are two atoms of aluminum in the substance.

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