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3 years ago

1) Which action defines a double-displacement reaction?

Chemistry

2 answers:

Ronch [10]3 years ago

5 0

Answer:

The action that defines a double displacement reaction is <u><em>option B) formation of a precipitate.</em></u>

Explanation:

A double displacement reaction occurs when two elements in different compounds exchange positions, forming two new compounds. In general, the exchange occurs between reagents that are ionic compounds in solution, where the anions and cations of the compounds are exchanged.

Double displacement reactions follow the following general chemical equation:

AB + CD ⇒ AD + CB

The initial compounds AB and CD react by exchanging "their partners" and therefore form two new compounds: AD and CB. For this type of reaction to occur, the products formed must be more stable or related than the reagents.

Since the reaction is a simple ion exchange, none of these gains or loses electrons. That is, these chemical reactions do not show changes in the number of oxidation or relative charge of the element. Therefore, if A is a +1 charge cation in compound AB, it will have the same +1 charge in compound AD.

On the other hand, a precipitation reaction occurs when two aqueous ionic compounds form a new ionic compound that is not soluble in water. That is, the reaction can occur between two ionic compounds (salts), if after the ion exchange one of the products is insoluble in water. This insoluble compound is called precipitate, since it will precipitate in the solution. So, it is an example of double displacement reactions.

Then, <u><em>the action that defines a double displacement reaction is option B) formation of a precipitate.</em></u>

jekas [21]3 years ago

3 0

Answer:

formation of a precipitate

Explanation:

When two salt solutions are mixed, an observable reaction is seen when two types of ions attract each other, they clump together and fall to the bottom of the container as a solid precipitate.

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Water flows over Niagara Falls at the average rate of 2,400,000 kg/s, and the average height of the falls is about 50 m. Knowing

Zinaida [17]

Answer:

1) The power of Niagara Falls is 1.176 × 10⁹ W

2) The number of 15 W LED light bulbs it could power is 78.4 × 10⁶ light bulbs

Explanation:

1) The Niagara falls water mass flow rate = 2,400,000 kg/s

The height of the fall = 50 meters

The gravitational potential energy = Mass (kg) × height (m) × gravity (9.8 m/s²)

The power = The energy converted per second = Mass flow rate (kg/s) × height (m) × gravity (9.8 m/s²)

Therefore;

The power of Niagara Falls= 2,400,000 kg/s × 50 m ×9.8 m/s²= 1.176 × 10⁹ W

The power of Niagara Falls = 1.176 × 10⁹ W

2) The number, n, of 15 W LED light bulbs it could power is given by the relation;

n × 15 W = 1.176 × 10⁹ W

∴ n = 1.176 × 10⁹ W/(15 W) = 78.4 × 10⁶ light bulbs

The number of 15 W LED light bulbs it could power = 78.4 × 10⁶ light bulbs.

6 0

3 years ago

Calculate the molality of a solution that contains 51.2 g of naphthalene, C10H8, in 500 mL of carbon tetrachloride. The density

PtichkaEL [24]

<u>Answer:</u> The molality of naphthalene solution is 0.499 m

<u>Explanation:</u>

Density is defined as the ratio of mass and volume of a substance.

$\text{Density}=\frac{\text{Mass}}{\text{Volume}}$ ......(1)

Given values:

Volume of carbon tetrachloride = 500 mL

Density of carbon tetrachloride = 1.60 g/mL

Putting values in equation 1, we get:

$\text{Mass of carbon tetrachloride}=(1.60g/mL\times 500mL)=800g$

Molality is defined as the amount of solute expressed in the number of moles present per kilogram of solvent. The units of molarity are mol/kg. The formula used to calculate molarity:

$\text{Molality of solution}=\frac{\text{Given mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Mass of solvent (in g)}}$ .....(2)

Given values:

Given mass of naphthalene = 51.2 g

Molar mass of naphthalene = 128.17 g/mol

Mass of solvent = 800 g

Putting values in equation 2, we get:

$\text{Molality of naphthalene}=\frac{51.2\times 1000}{128.17\times 800}\\\\\text{Molality of naphthalene}=0.499m$

Hence, the molality of naphthalene solution is 0.499 m

4 0

3 years ago

Calculate the mass of a substance with a density of 1.98 g/mL and a volume of 265 mL.

Vinvika [58]

Answer:

Explanation:

The density of a substance can be found by using the formula

$Density = \frac{mass}{volume}$

Making mass the subject we have

<h3>mass = Density × volume</h3>

From the question

Density = 1.98 g/mL

volume = 265 mL

Substitute the values into the above formula and solve for the mass

That's

mass = 1.98 × 265

We have the final answer as

Hope this helps you

8 0

3 years ago

A certain reaction has an activation energy of 51.64 kj/mol. At what temperature Kelvin will the reaction be 5.50 times faster t

pishuonlain [190]

For this, we use the Arrhenius equation to solve the problem. It is expressed as:
k = Ae^-(E/RT)

where k is the reaction rate, A is the pre-exponential factor, E is the activation energy and T is the temperature.

For a reaction, A is constant at different temperatures. We then isolate the constant and then introduce the second condition to the equation since it will still be equal to the constant. It is then simplified to:

ln(k2/k1) = -E/R (1/T2 - 1/T1)
ln(5.50k1/k1) = -51.64/8.314 (1/T2 - 1/343)
T2 = 379 K

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Mamont248 [21]

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