What is the particle of an atom that moves rapidly in a cloud like region around the nucleus

Catalytic converters made of palladium (Pd) reduce automobile pollution by catalyzing the reaction between unburned hydrocarbons

Setler79 [48]

Almost all catalysts work by lowering the activation energy of the reaction with no change in the free energy of the reaction

- So in this case we can say that palladium reduce automobile pollution by catalyzing the reaction between un-burned hydrocarbons and oxygen :

D. by decreasing the activation energy

3 0

3 years ago

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A student is using a coffee-cup calorimeter to determine the enthalpy change of the endothermic reaction of two aqueous solution

Liula [17]

Answer:

See the answer below

Explanation:

<em>First, it should be understood that an endothermic reaction is one that absorbs energy in the form of heat from the surrounding.</em> The products of endothermic reactions usually have higher energy than their reactants. Hence, the ΔH° which is referred to as the enthalpy change is usually positive.

<u>Forgetting to cover the coffee-cup calorimeter means some of the heat energy absorbed by the reactants would be exchanged back to the surroundings - a loss.</u> It also means that the enthalpy change would be smaller compared to if the cup had been covered because some of the heat has been lost to the surrounding.

8 0

3 years ago

Do you round when dividing significant figures

Tatiana [17]

Answer: You multiply and divide when rounding division significant figures

Explanation: Both multiplying and dividing significant figures have the same rule. That rule is, the FINAL ANSWER of a multiplication and division problem should be rounded to the number of significant figures that is the least amount of any figures used in the multiplication or division. Let us demonstrate below.

4 0

3 years ago

Which electromagnet would have the most strength?

ycow [4]

The one with 20 coils as it can generate more electricity.

8 0

3 years ago

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The density of a pure liquid at 25 degrees Celsius was calculated by determining the mass and volume of a sample of the liquid.

adelina 88 [10]

Answer

The density of the liquid is 0.82 g/mL.

Explanation:

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

Mass of empty flask = 18.990 g

Mass of flask + liquid = 39.439 g

Volume of liquid = 25 mL

Density of liquid =..?

Next, we shall determine the mass of the liquid. This can be obtained as follow:

Mass of empty flask = 18.990 g

Mass of flask + liquid = 39.439 g

Mass of liquid =.?

Mass of liquid = (Mass of flask + liquid) – (Mass of empty flask)

Mass of liquid = 39.439 – 18.990

Mass of liquid = 20.503 g

Finally, we shall determine the density of the liquid as follow:

Mass of liquid = 20.503 g

Volume of liquid = 25 mL

Density of liquid =..?

Density = mass / volume

Density of liquid = 20.503 / 25

Density of liquid = 0.82 g/mL

8 0

3 years ago