Question #21TrueFalse The general name for a substance added to a reaction that affects the rate but is not consumed in the reaction is called a complex a. True
b. False

Answer:

The answer to your question is 2.84 M

Explanation:

Data

mass of MgO = 57.3 g

volume of the solution = 500 ml

Process

1.- Calculate the molar mass of MgO

MgO = 24.3 + 16 = 40.3 g

2.- Calculate the moles of MgO

                 40.3 g MgO ----------------- 1 mol

                  57.3 g MgO -----------------  x

                          x = (57.3 x 1) / 40.3

                          x = 1.42 moles

3.- Calculate the Molarity

Molarity = moles / volume (l)

Volume = 0.5 liters

-Substitution

Molarity = 1.42 / 0.5

-Result

Molarity = 2.84

Final answer:

The molarity of the solution is 2.84 M.

Explanation:

To find the molarity of the solution, we need to first calculate the number of moles of MgO and the volume of the solution.

First, we convert the mass of MgO to moles using its molar mass. The molar mass of MgO is 40.31 g/mol, so:

moles of MgO = mass of MgO / molar mass of MgO

moles of MgO = 57.3 g / 40.31 g/mol = 1.42 mol

Next, we convert the volume of the solution to liters:

volume of solution = 500.0 mL / 1000 mL/L = 0.500 L

Finally, we divide the number of moles of MgO by the volume of the solution to find the molarity:

molarity = moles of solute / volume of solution

molarity = 1.42 mol / 0.500 L = 2.84 M

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The universe is expanding is as the galaxies are moving away from each other, and the temperature of the universe is decreasing. Therefore, option (1) is correct.

How is the universe expanding?

First scientists theorized that as the universe is expanding and its temperature has gradually decreased. The universe has been expanding since the Big Bang and, as it expands, it’s temperature cooling down.

The temperature of the universe can be measured by looking at the cosmicmicrowave background (CMB). The temperature an be estimated by the thermal radiation left over from the BigBang.

The CMB scientists have been investigating that its temperature has been dropping off gradually as our universe expands out and the current average temperature of the cosmos is estimated about 2.73 Kelvin.

The point of the Big Bang from the Big bang theory is described as densesingularity and infinitely hot. The energy from the Big Bang distributed as the universe expands and gives the cooling effect.

But new research suggests otherwise that the temperature of the earth is actually increasing as it expands.  Therefore, the temperature of universe increasing with its expansion.

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Answer:

Option (2)

Explanation:

The water in most of the region is generally pumped out of the ground for the purpose of irrigation. This rate of pumping is much higher than the rate of replenishment. The over-pumping of water leads to the lowering of the water table

About 60 to 70% of the water that is used for irrigation purposes does not reach the crop. It is because the water most of the time gets percolated down into the deeper zones. In addition to this, the water also leaks through the fractures that are associated with the canals and increasing rate of evaporation.

Thus, the correct answer is option (2).

Answer:b never reaches the crop hopefully helps

Explanation:

Answer: -

A chemical bond is

C) the force that holds together the elements in a compound.

Explanation: -

A chemical bond results when there is a transfer of electrons from 1 element to another or there is a sharing of electrons between two element atoms.

Due to this compounds are formed.

Hence A chemical bond is

C) the force that holds together the elements in a compound.

the correct answer should be c.

Answer:

               0.64 g of S

Solution:

               The balance chemical equation is as follow,

                                           2 Cu + S ----> Cu₂S

According to equation,

                        127 g (2 mole) Cu produces = 159 g (1 mole) of Cu₂S

So,

                                 2.54 g Cu will produce = X g of Cu₂S

Solving for X,

                     X = (2.54 g * 159 g) / 127 g

                     X = 3.18 g of Cu₂S

Now, it is confirmed that the reaction is 100% ideal. Therefore,

As,

                       127 g (2 mole) Cu required = 32 g (1 mole) of S

So,

                                2.54 g Cu will require = X g of S

Solving for X,

                      X = (2.54 g * 32 g) / 127 g

                      X = 0.64 g of S

Answer : The total mass of sulfur consumed will be, 0.64 grams and the chemical formula of the compound produced is, copper oxide.

Solution :

According to the law of conservation of mass, the total mass of reactant should be equal to the total mass of product.

The balanced chemical reaction will be,

In this reaction, copper and sulfur are the reactants and copper sulfide is the product.

Let the mass of sulfur be 'x' gram

According to the law of conservation of mass,

Therefore, the total mass of sulfur consumed will be, 0.64 grams and the chemical formula of the compound produced is, copper oxide.

To solve this we must be knowing each and every concept related to element. Therefore,  "all of the noble gas elements except neon have 8 electrons in their outermost energy level" is a false element.

What is element?

A chemical element represents a material that cannot be degraded chemically. Although chemical processes do not modify atoms, nuclear reactions can produce new elements.

Elements are classified according to the amount of protons they have. An element's atoms typically have the same amount of protons, but differing amounts of electrons or neutrons.

There are 118 recognized elements. Element 120.1 is being researched. When element 120 is created and validated, the periodic table must be updated to include it. A numerical subscript following an element in a chemical formula mean number of atoms. All of the noble gas elements except have 8 electrons in their outermost energy level.

Therefore,  "all of the noble gas elements except neon have 8 electrons in their outermost energy level" is a false element.

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