During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a ∆G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the ∆G for the new reaction?

Answers

Answer 1

Answer:

dG will be the same -20 kcal/mol

Explanation:

The dG can be expressed in terms of the G(products) - G(reactants). If the amount of enzyme is doubled the Gibbs energy of the reactants and products will be the same, so the substraction dG has the same value


Related Questions

A container has the dimensions of 10 cm x 50 mm x 0.2 m. It is filled completely with 5.0 kg of a powdery ore. What is the density of the ore in g/cm3 ? (D=m/V)

0.05 g/cm3

5.0 g/cm3

50 g/cm3

500 g/cm3

Answers

Answer:

B

Explanation:

5 kg = 5 kg * 1000 grams / kg = 5000 grams

10 cm does not require any conversion.

50 mm = 50 mm * 1 cm/10 mm = 5 cm

0.2 m = 0.2 m * 100 cm / 1 m = 20 cm

V = 10 cm * 5 cm * 20 cm

V = 1000 cm^3

Density = 5000 grams / 1000 cm^3 = 5 grams / cm^3

B

Is argon gas a pure substance or a mixture. Is iron oxide dust a pure substance or a mixture.

Answers

Answer:

See below.

Explanation:

Argon gas is a pure substance. It has nothing other than molecules of Argon gas.

Iron oxide is a compound with iron and oxygen as its components. It is a pure substance.

Is monosodium glutamate an element, compound, homogeneous mixture, or heterogeneous mixture?

Answers

Final answer:

Monosodium glutamate is a compound made up of sodium, carbons, hydrogen, nitrogen, and oxygen.

Explanation:

Monosodium glutamate is a compound.

It is the sodium salt of glutamic acid, a naturally occurring non-essential amino acid.

Compounds are substances made up of two or more elements that are chemically bonded together.

In this case, monosodium glutamate is made up of the elements sodium (Na), carbon (C), hydrogen (H), nitrogen (N), and oxygen (O).

The atomic weight of antimony is 121.75 u. There are two naturally occurring isotopes of antimony. 121Sb has an isotopic mass of 120.9038 u and has a natural abundance of 57.25%. What is the isotopic mass of the other isotope 123Sb?
1. 122.93 u
2. 122.88 u
3. 123.06 u
4. 122.97 u
5. 122.82 u

Answers

Final answer:

The isotopic mass of 123Sb can be calculated using the equation for atomic weight, taking into account the percentage abundance of each isotope of antimony. Solving this equation, the isotopic mass of 123Sb is determined to be approximately 122.93 u.

Explanation:

To calculate the isotopic mass of 123Sb, we should make use of the equation that defines atomic weight. The atomic weight is the weighted average of the isotopic masses, factoring in the percentage abundance of each isotope.

The equation can be represented as follows:

Atomic weight = (mass isotope 1 x percentage abundance isotope 1) + (Mass isotope 2 x percentage abundance isotope 2)

Plugging in the known values,

121.75 u = (120.9038 u x 57.25%) + (Mass 123Sb x (100% - 57.25%))

By rearranging the equation and solving it, we can find the mass of 123Sb to be around 122.93 u

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A sample of aluminum is placed in a 25 ml graduated cylinder containing 10 mL of water. The level of water rises to 18 mL. Aluminum has a density of 2.7 g/mL. Calculate the mass of the sample

Please include explanation if possible

Answers

To determine the mass of the sample, first find the volume difference after and before the aluminum was placed, the volume change is equal to the volume of the submerged object, in this case aluminum.

Then knowing volume of aluminum and the density of it, we can solve for the mass.

D = m/v

Dv = m

2.7 g/ml • 8 ml = 21.6 grams.

Answer: The mass of sample is 21.6 grams.

Explanation:

We are given:

Volume of cylinder without object, [tex]V_1[/tex] = 10 mL

Volume of cylinder with object, [tex]V_2[/tex] = 18 mL

Volume of object = [tex]V_2-V_1=18-10=8mL[/tex]

To calculate volume of a substance, we use the equation:

[tex]\text{Density of a substance}=\frac{\text{Mass of a substance}}{\text{Volume of a substance}}[/tex]

We are given:

Density of sample (aluminum) = 2.7 g/mL

Volume of sample (aluminum) = 8 mL

Putting values in above equation, we get:

[tex]2.7g/mL=\frac{\text{Mass of a sample}}{8mL}\\\\\text{Mass of object}=21.6g[/tex]

Hence, the mass of sample is 21.6 grams.

If you have 2.50 moles of AgNO3, how many moles of Ba(NO3)2 can be formed? ________
show work

Answers

Answer:

1.25 moles of Ba(NO3)2 will be formed.

Explanation:

Given data:

moles of AgNO3 = 2.50 mol

moles of Ba(NO3)2 = ?

Solution:

First of all we will write the balance chemical equation.

2AgNO3 + BaCl2 → Ba(NO3)2 + 2AgCl

Now we compare the moles of AgNO3 and  Ba(NO3)2.

   AgNO3   :    Ba(NO3)2

     2           :        1

     2.5        :        1/2 × 2.5 = 1.25 moles

so, 2.50 moles of AgNO3 will produce 1.25 moles of Ba(NO3)2.

Which functional group is found in methyl ethanoate

Answers

Answer:

ester

Explanation:

methyl ethanoate is also known as methyl acetate

Answer : The correct option is, (b) R-COO-R'

Explanation :

Methyl ethanoate is also known as acetic acid methyl ester or methyl acetate. It is a carboxylate ester.

The formula of methyl ethanoate is, [tex]CH_3COOCH_3[/tex]

As we know that there are many functional groups which are:

(1) R-OH : It belongs to an alcoholic functional group in which the the -OH group is directly attached to the alkyl group of carbon.

(2) R-O-R' : It belongs to an ether functional group in which the the oxygen is directly attached to the two alkyl group of carbon.

(3) R-CO-R' : It belongs to ketone functional group in which the the -CO group is directly attached to the two alkyl group of carbon.

(4) R-CHO : It belongs to an aldehyde functional group in which the the -CHO group is directly attached to the alkyl group of carbon.

(5) R-COOH : It belongs to carboxylic acid functional group in which the the -COOH group is directly attached to the alkyl group of carbon.

(6) R-COO-R' : It belongs to ester functional group in which the the -COO group is directly attached to the two alkyl group of carbon.

From this we conclude that, the functional group found in methyl ethanoate is, ester.

Hence, the correct option is, (b) R-COO-R'

How many grams of water are theoretically produced for the following reaction given we have 2.6 moles of HCl and 1.4 moles of Ca(OH)2? Reaction: 2HCl + Ca(OH)2 → 2H2O + CaCl2 A) 25.2 B) 50.4 C) 46.8 D) 103.6 E) not enough information

Answers

Answer:

The answer to your question is: 6.8 g of water

Explanation:

Data

2.6 moles of HCl

1.4 moles of Ca(OH)2

                           2HCl     +     Ca(OH)2    →        2H2O    +      CaCl2

MW                   2(36.5)               74                       36 g               111 g

                          73g                

                            1 mol of HCl ----------------  36.5 g

                           2.6 mol           --------------    x

                              x = (2.6 x 36.5) / 1   = 94.9 g

                           1 mol of Ca(OH)2 --------------   74 g

                         1.4 mol                  ---------------   x

                            x = (1.4 x 74) / 1  = 103.6 g

Grams of water

                        73 g of HCl ------------------   36g of H2O

                        94.9 g        -------------------    x

                     x = (94.9 x 36) / 73 = 46.8 g of water

The amount of water is theoretically produced for the following reaction given we have 2.6 moles of HCl and 1.4 moles of Ca(OH)₂ -  C) 46.8.

Given:

2HCl + Ca(OH)₂ -------------> CaCl₂ + 2H2O

in this reaction, 2 moles HCl reacts with 1 mole Ca(OH)₂

which means 2.6 moles of HCl reacts with 2.6 x = 1.3

but we have 1.4 moles Ca(OH)₂  it is the excess reagent

Solution:

HCl is a limiting reagent in this reaction as it allows producing the mole of water on the base of the number of moles it has,

=> 2 mole HCl - 2 moles of H₂O

Here, 2.6 moles of HCl would give 2.6 moles of H₂O only

=> convert moles to mass  

moles = mass / molar mass  

and,

mass = [tex]\frac{mass}{molar\ mass}[/tex]

mass = 2.6 x 18

= 46.8 g

Thus, the amount of water is theoretically produced for the following reaction given we have 2.6 moles of HCl and 1.4 moles of Ca(OH)₂ -  C) 46.8.

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In two or more complete sentences, compare singe displacements reactions and double displacement reactions

Answers

Answer:

The answer is in the explanation

Explanation:

Single displacement reactions: In these reactions, a more reactive element kicks out a less reactive element from a compound.

Ex.  Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g)

In this example, Zn is more reactive than H, then Zn displaces H from the compound.

Double displacement reactions: In these kind of reactions 2 elements are displaced from the different compounds, these elements interchange positions.

Ex. CuCl2(aq) + 2 AgNO3(aq) → Cu(NO3)2(aq) + 2 AgCl(s)

In the example, Cu displaces Ag and Ag displaces Cu, they interchange positions.

Final answer:

Single displacement reactions involve one element replacing another in a compound, whereas double displacement reactions involve the exchange of ions between two compounds, often forming a precipitate.

Explanation:

Single displacement reactions and double displacement reactions are two different types of chemical reactions. In a single displacement reaction, an element replaces another element in a compound, typically following the pattern A + BC → AC + B, where A is a single element and BC is a compound. By contrast, a double displacement reaction, also known as a metathesis, involves the exchange of ions between two compounds, conforming to the general form AB + CD → AD + CB, often resulting in the formation of a precipitate when one of the new compounds is insoluble.

An atom has 27 protons and 32 neutrons. Which of the following symbols is correct for this atom?

59Co
32Co
59Ge
27Ge

Answers

Final answer:

The atom with 27 protons and 32 neutrons is represented as 59Co. The number is calculated by adding protons and neutrons which is the mass number, and the protons determine the element symbol.

Explanation:

The correct symbol for the atom is based on the number of protons it contains. The atomic number, which is what the number of protons is known as, identifies the element. In this case, 27 protons correspond to the element cobalt (Co). The mass number of an element is the sum of protons and neutrons, so in this atomic configuration, the total would be 27 protons + 32 neutrons = 59. Therefore, the correct symbol for this atom is 59Co.

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Which half-reaction correctly describes an oxidation?

Answers

Answer:

The answer to yourquestions is the last option

Explanation:

Cr(s) -------------------- Cr +3 (aq) + 3e-

Avogadro's law states that the _____ of a gas is directly proportional to the _____ of the gas when _____ stay the same

Answers

Answer:

The three blanks for this answer, are

1. volumen

2. moles

3. Temperature and pressure.

So, Avogadro's law states that the volume of a gas is directly proportional to the moles of the gas when temperature and pressure stay the same

Explanation:

Imagine you have 10 moles of a gas which is contained in 50 L. How many moles of that gas, you will have if the volumen has been reduced to 10 L. (Of course, don't forget that T° and pressure are the same)

There is an equation like this, initial moles /initial volume = moles at the end/volume at the end, (Avogadro law for gases), so 10/50 =moles at the end/10.  When u operate, moles at the end = (10 x 10) / 50.

Moles at the end are 2. Did u get it?. Volumen has been reduced, also the moles.

Final answer:

Avogadro's law states that the volume of a gas is directly proportional to the amount of the gas when temperature and pressure stay the same.

Explanation:

Avogadro's law states that the volume of a gas is directly proportional to the amount (moles) of the gas when temperature and pressure stay the same. This law is based on Avogadro's principle which states that equal volumes of gases, at the same temperature and pressure, contain an equal number of particles (atoms, molecules, or ions).

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Which of the following is NOT a type of carbohydrate molecule? Choose one: A. A disaccharide B. A glucose molecule C. A triglyceride D. A polysaccharide

Answers

Answer:

The correct answer is C: A triglyceride

Explanation:

A carbohydrate is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms. A carbohydrate is is a synonym of saccharide.

A triglyceride  is an ester derived from glycerol and three fatty acids. So not a saccharide. The other 3 options all are saccharides. Triglycerides are the main constituents of body fat.

Final answer:

Triglyceride is not a type of carbohydrate molecule. It's a type of fat found in the blood, while disaccharides, glucose molecules and polysaccharides represent different types of carbohydrates.

Explanation:

Among the choices A. A disaccharide, B. A glucose molecule, C. A triglyceride, and D. A polysaccharide, option C. A triglyceride is NOT a type of carbohydrate molecule. Instead, triglycerides are a type of fat found in the blood. A person's body converts calories it doesn't need for energy into triglycerides. On the other hand, disaccharides, glucose molecules and polysaccharides are all different types of carbohydrates, which are molecules consisting of carbon, hydrogen, and oxygen atoms.

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Which statement about hydrogen bonding is true? Select one:
a. Hydrogen bonding is the intermolecular attractive forces between two hydrogen atoms in solution.
b. The hydrogen bonding capabilities of water molecules cause CH3CH2CH2CH3 to be more soluble in water than CH3OH.
c. Hydrogen bonding of solvent molecules with a solute will not affect the solubility of the solute.
d. Hydrogen bonding interactions between molecules are stronger than the covalent bonds within the molecule.
e. Hydrogen bonding arises from the dipole moment created by the unequal sharing of electrons within certain covalent bonds within a molecule.

Answers

Answer:

E.

Explanation:

All answers other than E have the incorrect bonding capabilities or other incorrect information.

Final answer:

The true statement about hydrogen bonding is e. Hydrogen bonding arises from the dipole moment created by unequal sharing of electrons within certain covalent bonds within a molecule, making hydrogen bonds a special type of intermolecular force.

Explanation:

The correct statement about hydrogen bonding is that it arises from the dipole moment created by the unequal sharing of electrons within certain covalent bonds within a molecule. Therefore, the answer to the question is e. Hydrogen bonding arises from the dipole moment created by the unequal sharing of electrons within certain covalent bonds within a molecule. Hydrogen bonds are a significant intermolecular force found in molecules where a hydrogen atom is covalently bonded to a very electronegative atom, such as nitrogen (N), oxygen (O), or fluorine (F). These bonds are quite polar, leading to a strong dipole-dipole interaction that falls under a particular intermolecular force category referred to as hydrogen bonding. Hydrogen bonds are notably stronger than van der Waals interactions but are much weaker than covalent or ionic bonds. A typical hydrogen bond's strength is about 5% of a covalent bond's strength.

You purchase a bottle of concentrated sulfuric acid from a chemical supplier. The bottle reads Sulfuric acid (95% w/w) plastic coated safety bottle. The label lists the density of the acid as 1.85 g/mL and the molar mass as 98.08 g/mol, but the label fails to list the molarity of the concentrated acid! Calculate the molarity of the sulfuric acid based upon the information given.

Answers

Answer:

The molarity of the sulfuric acid is 0.018 M

Explanation:

The molarity of a solution is the number of moles of the solute (sulfuric acid in this case) in a 1-liter solution.

Every 100 g of the solution, we have 95 g sulfuric acid because its concentration is 95% w/w.

With the density, we can calculate how many liters are 100 g of solution:

density = mass / volume

1.85 g / ml = 100 g / volume

volume = 100 g / 1.85 g/ml

volume = 54.1 ml or 0.0541 l

Now, we know that we have 95 g sulfuric acid in 0.0541 l solution. In 1 l, we have then:

1 l * 95g / 0.0541 l = 1.756 g sulfuric acid.

But we want to know how many moles sulfuric acid we have per liter. Then, using the molar mass, we can calculate how many moles there are in 1.756 g sulfuric acid:

1.756 g * 1 mol / 98.08 g = 0.018 mol

The molarity is 0.018 M

The rate of a reaction is dependent upon ___________ and ___________.A. the frequency of collisions between particles, the energy of the collisions B. the pressure of the system, the polarity of the reactants C. the frequency of collisions between particles, the size of the particles D. the size of the particles, the electronegativity of the reactants.

Answers

Answer:

c. The frequency of collisions between particles, the size of the particles.

Explanation:

The reaction among 2 substances could speed up if the size of particles is smaller, for example it is easier to dissolve the common sugar than a cube of sugar, the reason is because since the size is smaller, the total area that is exposed to react is bigger.

Also, the frequency of collisions between particles, can increase the rate of reaction, because if they collide faster, the probability of react is bigger.

Answer:

c

Explanation:

You determine that your compound is soluble in the acetone, but not the water, aqueous hydrochloric acid or aqueous sodium hydroxide solutions. You therefore conclude that the one characteristic of your compound is that it is ____________________ .

Answers

Answer:

Explanation:

Given the characteristics:

acetone is a non polar molecule

water, NaOH and HCl in water, the three of them are highly polar molecules

So then, the unknown compound is a non polar molecule.

One of the first mixtures of metals called amalgam used by densities for tooth fillings consisted of 26 g of silver, 10.8 g of tin, 2.4 g of copper, and .8 g of zinc, how much silver is in a 26 g sample of amalgam?

Answers

Answer:

The answer to your question is : 16.9 g of Ag

Explanation:

Data

26 g Ag

10.8 g of Sn

2.4g Cu

0.8 Zn

Ag = ? in 26 g of sample

Total mass in the amalgam = 26 + 10.8 + 2.4 + 0,8 = 40 g

Rule of three

                              40 g of sample  -------------- 26 g of silver

                               26 g of sample --------------   x

                           x = (26 x 26) / 40

                          x = 16.9 g of Silver

Final answer:

A 26 g sample of amalgam contains 16.9 g of silver, which is calculated based on the proportion of silver in the original amalgam mixture.

Explanation:

The student's question pertains to the calculation of the amount of silver in a 26 g sample of amalgam, which is a mixture of several metals. The total mass of the original amalgam mixture consists of 26 g of silver, 10.8 g of tin, 2.4 g of copper, and 0.8 g of zinc, which adds up to a total of 40 g. To find the amount of silver in a 26 g sample of this amalgam, we use the concept of proportion.

First, we calculate the percentage of silver in the original amalgam:

(mass of silver / total mass of amalgam) × 100 = (26 g / 40 g) × 100 = 65%

Now, we can find the mass of silver in the given 26 g sample of amalgam by multiplying the total mass of the sample by the percentage of silver:

(percentage of silver / 100) × mass of sample = (65 / 100) × 26 g = 16.9 g

Therefore, a 26 g sample of amalgam contains 16.9 g of silver.

Procedure for the experiment.
1. Crush 1 stick of classroom chalk (a mixture of limestone and gypsum) finely.
2. Mix chalk into 50 ml of water in a beaker.
3. Pour the mixture through filter paper into another beaker. The water appears to be "pure."
4. Boil the water or let it evaporate away.
What is left?

Answers

Answer:

A solid residue of limestone and some gypsum.

Explanation:

In step 2, some of the limestone and gypsum in the chalk dissolve in the water. When the mixture is filtered, the dissolved substances remain in the water. When the water is boiled off or evaporated, the solid substances remain behind.

a faucet is leaking water at a speed of 5 drops per minute. If 1 ml is equivalent to 10 drops, how many liters of water will be wasted in one day

Answers

Answer: 0.72 litres of water is wasted in one day.

Explanation:

First you need to find out how many minutes are in a day. Do this by multiplying the number of minutes in an hour (60) by the number of hours in a day (24). 24 x 60 = 1440. If the faucet is dripping at 5 drops per minute, then multiply 5 by the number of minutes in a day (1440) to see how many drops drip in one day. 5 x 1440 = 7200. Now we need to figure out how many mL fo water that is. if 10 drops is 1 mL, then we need to divide the total number of drops (7200) by 10. 7200 divided by 10 is 720. That means 720 mL of water is dripping per day. Finally, we must convert mL to litres. There are 1000 mL in one litre, so divide 720 by 1000. The final answer is 0.72

As the Collection of physical evidence begins

a.The police chief has primary responsibility of maintaining the chain of custody.

b.All observations should be recorded through photographs, sketches and notes.

c.The district attorney should be consulted for admissibility of physical evidence in court.

d.The medical examiner should oversee the collection of the evidence at the crime scene.


5.The most important prerequisite for photographing a crime scene is:


a.For items to be placedinto indirect light so that nuances can be picked up in the photograph.


b.For the crime scene to be in an unaltered condition.


c.For the photographer to start with close-ups of any important object and back up to get the full scale.


d.For rulers or other items to be placed into the photographs to show scale.

Answers

Explanation:Once the crime scene has been thoroughly documented and the locations of the evidence noted, then the collection process can begin

Answer: d.The medical examiner should oversee the collection of the evidence at the crime scene.

Explanation:

The physical evidence includes all the evidences which shows the proximity of victim or culprit with the crime scene. The medical examiner should help in collection of the evidences at the scene of crime. The medical examiner can search and identify physical evidences such as blood, sweat, vomit, fecal matter, urine, bodily tissues as an evidence and can begin the process of collection without contamination.

An administrator in a very large company wants to estimate the mean level of nitrogen oxides (NOX) emitted in the exhaust of a particular car model in their very large fleet of cars. Historically, nitrogen oxide levels have been known to be Normally distributed with a standard deviation of 0.15 g/ml. What is the parameter of interest that the administrator wants to estimate?

Answers

Answer:

Explanation:

For very well describe a normal distribution, it is needed the mean and the standard deviation. We are only lacking the mean to properly describe the nitrogen levels emitted by the vehicles. He would like to measure the emitted NOX so he could properly model this phenomena.

Ammonia can be produced via the chemical reaction N2(g)+3H2(g)⇌2NH3(g) During the production process, the production engineer determines the reaction quotient to be Q = 3.56×10−4. If K = 6.02×10−2, what can be said about the reaction?

Answers

Answer:

Q<K so N2(g) +3H2(g) → 2NH3(g)

Explanation:

Step 1: Data given

For the balanced equation N2(g)+3H2(g)⇌2NH3(g)   We have the following data:

⇒ Reaction quotient Q = 3.56 *10^-4

  Where Q is defined as Q = [NH3]^2/{[N2]*[H2]^3]

⇒ Equilibrium constant K = 6.02 * 10^-2

 

If we compare Q and K, there are 3 options

⇒ Q > K : The reaction favors the reactants. This means that in the  Q  equation, the ratio of the concentration or pressure of the products) to the concentration or pressure of the reactants is larger than that for  K.

This means that more products are present than there would be at equilibrium.

Following Le chatelier's principle reactions always tend toward equilibrium, this means the reaction will produce more reactants from the excess products, and will therefore cause the system to shift to the LEFT.

Doing this, it will allow   the system to reach equilibrium.

⇒ Q = K : The reaction  is already at equilibrium. There is no tendency to form more reactants or more products at this point. No side is favored and no shift will occur.

⇒ Q < K  : The reaction favors the products. The ratio of products to reactants is less than that for the system at equilibrium—the concentration or the pressure of the reactants is greater than the concentration or pressure of the products.

Following Le chatelier's principle reactions always tend toward equilibrium,  the system shifts to the RIGHT to make more products.

In this case K > Q since 6.02*10^-2 > 3.56*10^-4

This means that forward reaction will be favored or the reaction will shift to the right

N2(g) +3H2(g) → 2NH3(g)

As a result, the reaction will consume nitrogen gas (N2) and hydrogen gas (H2), and produce more ammonia (NH3).

The reaction will proceed in this direction until equilibrium is established

Final answer:

The reaction quotient (Q) is less than the equilibrium constant (K), indicating that the forward reaction is favored. Therefore, the reaction shifts towards the production of more ammonia (NH3) to achieve equilibrium.

Explanation:

The reaction quotient (Q) and the equilibrium constant (K) are critical in determining the direction of a chemical reaction. In this scenario, the reaction of nitrogen and hydrogen to generate ammonia is considered. The reaction quotient Q is 3.56×10-4, while the equilibrium constant K is 6.02×10-2.

In situations where Q < K, the reaction progresses in the forward direction to reach equilibrium, meaning the formation of ammonia (NH3) is favored. On the other hand, if Q > K, the reaction would proceed in the reverse direction, favoring the formation of nitrogen and hydrogen. Therefore, given Q is less than K in this case, the reaction will shift toward the production of ammonia to establish equilibrium.

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In the process of attempting to characterize a substance, a chemist makes the following observations. Which are physical properties and which are chemical properties?
(a) The substance is a silvery white, lustrous metal
(b) It melts at 649°C and boils at 1105°C
(c) Its density at 20°C is 1.738 g/cm3
(d) The substance burns in air, producing an intense

Answers

Answer: a) The substance is a silvery white, lustrous metal :physical property.  

b) It melts at 649°C and boils at 1105°C : physical property.  

c) Its density at 20°C is [tex]1.738 g/cm^3[/tex]: physical property.  

d)  The substance burns in air, producing an intense white light : chemical property

Explanation:

Chemical property is defined as the property of a substance which is observed during a reaction where the chemical composition identity of the substance gets changed.

Physical property is defined as the property which can be measured and whose value describes the state of physical system. For Example: State, density etc.

a) The substance is a silvery white, lustrous metal is a physical property

b) It melts at 649°C and boils at 1105°C is a physical property.  

c) Its density at 20°C is [tex]1.738 g/cm^3[/tex] is a physical property.  

d) The substance burns in air, producing an intense white light is a chemical property

Final answer:

Observations (a), (b), and (c) regarding the metal's appearance, melting and boiling points, and density are physical properties. Observation (d) describes a chemical property, as it involves the substance's ability to burn in air.

Explanation:

In the process of characterizing a substance, a chemist observes certain properties which can be classified as either physical properties or chemical properties.

(a) The substance being a silvery white, lustrous metal is a physical property, as it describes the substance's appearance without altering its composition.(b) Melting at 649°C and boiling at 1105°C are also physical properties, since they describe conditions in which the substance changes state but not composition.(c) Having a density of 1.738 g/cm³ at 20°C is another physical property, which involves measuring a characteristic that does not involve changing the substance itself.(d) The substance's ability to burn in air, which implies a reaction with oxygen to produce a new substance, is a chemical property.

need help with chem! (multiple choice)

Answers

Answer:

C

Explanation:

Atoms undergoing alpha decay lose 2 protons and two neutrons to become a different atom. Those two protons and neutrons are represented by an α (the symbol for alpha) particle which also represents a helium nucleus (2 neutrons and 2 protons).  

C because of what she said

When water and hydroxide approach, will the two oxygen atoms attract or repel one another? They will attract by bonding like the oxygens in hydrogen peroxide, h-o-o-h. They will attract because they both carry negative charges. They will repel because they both carry negative charges. They will repel because atoms of the same element always repel?

Answers

Answer:

They will repel because they both carry negative charges.

Explanation:

When water approaches hydroxide ions, the oxygen atoms will repel each other. Water on its own is a polar covalent compound. It has a positive and negative end.

Hydroxide is radical that is negatively charged. It consists of oxygen and hydrogen atoms.

The like charges on the oxygen atom will repel one another as a general rule of attraction. The oxygen will have more affinity for the hydrogen.

Which element would have this representation: 43 ? 21 Question 4 options: Technetium Scandium Titanium Cobalt

Answers

Answer:

The naswer to your question is Scandium

Explanation:

43 means the atomic mass is normally presented as a power

21 means atomic number is always a subscript

                   ₂₁ ? ⁴³

Technetium             ₄₃Tc⁹⁸

Scandium                 ₂₁Sc⁴⁴      

Titanium                   ₂₁Ti⁴⁷

Cobalt                      ₂₇Co⁵⁹

Answer:

B. Scandium is the answer

Explanation:

[tex]Sc^{43}_{21}[/tex]

When we look at this Nuclide symbol we get to know that 21 is the atomic number as it is in the subscript and 43 is the mass as it is in the superscript.

We identify an element from its atomic number by looking at the periodic table.

Atomic number 21 is element Scandium. Sc-43 is one of the isotope mentioned here.

We don’t use mass number to identify an atom.

What should you do with a rag that has been used to wipe up spilled gasoline? a)Place it in the bilge. b)Hang it over the gunwale. c)Put it in the cockpit to air dry. d)Dispose of it on shore.

Answers

Answer:

A rag contaminated with gasoline is considered a hazard waste. The question seems to be asked to ask for indications of rag disposal on a ship, and if so, the answer is d) Discard it on land BUT with special precautions

Explanation:

Gasoline is a highly flammable organic solvent that is used as fuel. For the above is a dangerous substance. while the ship reaches the mainland, the rag must be stored avoiding contact with environmental agents such as the sun, pets or food. Once in a dry land the rag can be delivery for accurate disposal.

I hope my answer helps you

In a titration of hno3, you add a few drops of phenolphthalein indicator to 50.00 ml of acid in a flask. You quickly add 20.00 ml of 0.210 m naoh but overshoot the end point, and the solution turns deep pink. Instead of starting over, you add 30.00 ml of the acid, and the solution turns colorless. Then, it takes 7.23 ml of the naoh to reach the end point. What is the concentration of the hno3 solution

Answers

Answer:

The HNO3 solution has a concentration of 0.07 M

Explanation:

Step 1: find a balanced equation

HNO3 (aq) + NaOH (aq) → NaNO3 (aq) + H2O (l)

⇒ for 1 mole of HNO3 reacted, there will also react 1 mole of NaOH, and be produced 1 mole of NaNO3 and 1 mole of H2O, since the ratio is 1:1

Step 2: Calculating moles

Since we know that for 1 mole of HNO3 there will react 1 mole of NaOH, we can calculate the number of moleNaOH

⇒ Concentration = mole / volume

⇒ 0.210 = mole / ((20 + 7.23 ml) *10^-3)

mole = 0.005733 mole NaOH  = 0.005733 mole HNO3

Step 3: Calculating the concentration of HNO3

Concentration = mole / volume

C(HNO3) = 0.005733 mole / ((50 + 30 ml) *10^-3)

C(HNO3) = 0.07 M

The HNO3 solution has a concentration of 0.07 M

To control this we can calculate through the following formule:

0.02723L x 0.21 M x ( 1mol HNO3 / 1 mol NaOH) x (1/ 0.08L) = 0.07M

Final answer:

In a titration using phenolphthalein as an indicator, the concentration of HNO3 can be determined by considering the amount of NaOH used to reach the end point twice. The final concentration of the nitric acid (HNO3) solution is calculated to be approximately 0.0715 M.

Explanation:

We need to calculate the concentration of the HNO3 solution. In a titration of HNO3, we used a phenolphthalein indicator and added 20.00 mL of 0.210 M NaOH, passed the end point and reached a deep pink color solution. After erroneously overshooting the end point, you add 30.00 mL of HNO3 to the solution which then turns colorless. Finally, you add an additional 7.23 mL of NaOH to once again reach the end point.

Let's write out the balanced equation for the reaction:

HNO3 + NaOH → NaNO3 + H2O

From the complete balanced equation above, we can see that one mole of NaOH reacts with one mole of HNO3, so the same amount of moles of NaOH that react is the number of moles of HNO3 in the acid solution.

The total volume of NaOH solution used to neutralize the HNO3 is 20.00 + 7.23 = 27.23 mL, which is 0.02723 L.

We can find the number of moles of NaOH by multiplying the volume (in liters) by the molarity: 0.02723 L * 0.210 mol/L = 0.0057213 moles of NaOH

Since the total volume of HNO3 solution is 50.00 + 30.00 =80.00 ml or 0.080 L, the concentration of HNO3 can therefore be calculated as follows:

Concentration = mole / volume = 0.0057213 mol / 0.080 L = 0.0715 M.

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Consider the solutions, 0.04 m urea [(NH2)2C=O)], 0.04 m AgNO3 and 0.04 m CaCl2. Which has (i) the highest osmotic pressure, (ii) the lowest vapor pressure, (iii) the highest boiling point?

Answers

Final answer:

The solution with the highest number of particles in solution (CaCl2 in this case), experiences the highest osmotic pressure, lowest vapor pressure and highest boiling point due to the principles of colligative properties.

Explanation:

The question pertains to the colligative properties of solutions, which would be governed by the number of particles in the solution. The solutions are 0.04 m urea [(NH2)2C=O)], 0.04 m AgNO3, and 0.04 m CaCl2. For (i) Highest osmotic pressure, the solution with the highest ion count would yield the highest osmotic pressure. CaCl2 dissociates into three ions (Ca²+, and 2 Cl¯), therefore, it would exhibit the highest osmotic pressure. For (ii) Lowest vapor pressure, this would coincide with the solution with the highest osmotic pressure, again making it CaCl2, due to the greatest decrease in vapor pressure. For (iii) the highest boiling point, this too would be CaCl2 for the reasons stated above. The presence of more particles in a solution interferes more with the evaporation process, requiring more energy (higher temperature) to achieve boiling.

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