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3 years ago

Which of the following is not a catalyst? A. Nickel B. Platinum C. Enzymes D. Phosphorus

Chemistry

2 answers:

Bogdan [553]3 years ago

7 0

Answer:

The correct answer is D. Phosphorus is not a catalyst.

Explanation:

A catalyst is a substance that accelerates a chemical reaction at a certain temperature, but does not itself wear off the reaction. It is involved in the chemical reaction but is not the starting or end product of the reaction.

Catalysts create an alternative reaction pathway for the reaction with a lower activation energy. Activation energy is the energy required for the reaction to take place. However, the catalyst cannot cause a reaction which does not take place without the catalyst.

Depending on the phases in which the catalyst and reactants are present, one speaks of homogeneous or heterogeneous catalysts. Biochemical processes are catalyzed by enzymes, while heterogeneous catalysts are metals, such as platinum and nickel.

Mazyrski [523]3 years ago

6 0

The answer would be D because from my research it's the only one that didn't have a catalyst

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Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation isC7H6

prisoha [69]

Answer:

For a: The mass of acetic anhydride needed is 73.91 grams.

For b: The theoretical yield of aspirin is 130.43 grams.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For a:

Given mass of salicylic acid = $1.00\times 10^2g=100g$

Molar mass of salicylic acid = 138.121 g/mol

Putting values in equation 1, we get:

$\text{Moles of salicylic acid}=\frac{100g}{138.121g/mol}=0.724mol$

For the given chemical reaction:

$C_7H_6O_3+C_4H_6O_3\rightarrow C_9H_8O_4+CH_3COOH$

By stoichiometry of the reaction:

1 mole of salicylic acid reacts with 1 mole of acetic anhydride.

So, 0.724 moles of salicylic acid will react with = $\frac{1}{1}\times 0.724=0.724mol$ of acetic anhydride.

Now, to calculate the mass of acetic anhydride, we use equation 1:

Moles of acetic anhydride = 0.724 moles

Molar mass of acetic anhydride = 102.09 g/mol

Putting values in equation 1, we get:

$0.724mol=\frac{\text{Mass of acetic anhydride}}{102.09g/mol}\\\\\text{Mass of acetic anhydride}=73.91g$

Hence, the mass of acetic anhydride needed is 73.91 grams.

For b:

By stoichiometry of the reaction:

1 mole of salicylic acid is producing 1 mole of aspirin.

So, 0.724 moles of salicylic acid will produce = $\frac{1}{1}\times 0.724=0.724mol$ of aspirin.

Now, to calculate the mass of aspirin, we use equation 1:

Moles of aspirin = 0.724 moles

Molar mass of aspirin = 180.158 g/mol

Putting values in equation 1, we get:

$0.724mol=\frac{\text{Mass of aspirin}}{180.158g/mol}\\\\\text{Mass of aspirin}=130.43g$

Hence, the theoretical yield of aspirin is 130.43 grams.

4 0

3 years ago

What is the boiling point elevation constant, Kb, of diethyl ether if 38.2 g of the nonelectrolyte benzophenone, C6H5COC6H5, dis

kakasveta [241]

Answer: the boiling point elevation constant is $1.73^0C/m$

Explanation:

Elevation in boiling point is given by:

$\Delta T_b=i\times K_b\times m$

$\Delta T_b=T_b-T_b^0=$ = Elevation in boling point

i= vant hoff factor = 1 (for non electrolyte)

$K_b$ =boiling point constant = ?

m= molality

$\Delta T_b=i\times K_b\times \frac{\text{mass of solute}}{\text{molar mass of solute}\times \text{weight of solvent in kg}}$

Weight of solvent (diethylether)= 330 g = 0.33 kg

Molar mass of solute (benzophenone)= 182 g/mol

Mass of solute (benzophenone) = 38.2 g

$(35.7-34.6)^0C=1\times K_b\times \frac{38.2g}{182g/mol\times 0.33kg}$

$K_b=1.73^0C/m$

Thus the boiling point elevation constant is $1.73^0C/m$

3 0

2 years ago

explain how to determine the number of atoms, cations, and anions in ionic compounds. use an example to explain.

Damm [24]

Answer:

use coefficients and subscripts to determine how many atoms are in a compound. If there is no subscript or coefficient, assume it is 1. If there is a coefficient, multiply it with the subscripts. For counting cations and anions, determine first which is the anion and cation (anion = nonmetal, cation = metal), then count the number of that ion.

Example:

NaCl

one atom of Na, one atom of Cl. Since Na is a metal, it is a cation. Cl is a nonmetal, so it is an anion.

2CaCl2

2 atoms of Ca, 4 atoms of Cl. There are 2 cations, since Na is a metal, and 4 anions since Cl is a nonmetal

8 0

2 years ago

How did the uncertainty principle influence thinking about the arrangement of electrons in atoms?

pishuonlain [190]

Answer:

The correct answer is option C

Explanation:

According to Heisenberg's principle "At the instant of time when the position is determined, that is, at the instant when the photon is scattered by the electron, the electron undergoes a discontinuous change in momentum. This change is the greater the smaller the wavelength of the light employed, i.e., the more exact the determination of the position. At the instant at which the position of the electron is known, its momentum therefore can be known only up to magnitudes which correspond to that discontinuous change; thus, the more precisely the position is determined, the less precisely the momentum is known".

Hence, this principle made scientists to realize that electrons could not be located in defined orbits which a contradictory of Bohr's model.

3 0

3 years ago

21) Scientists represent elements by using a formulas b. subscripts c. symbols d. words

Hunter-Best [27]

They represent elements by using symbols

4 0

3 years ago