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3 years ago

Which of the following is an exothermic reaction?

2 answers:

4 0

I think the correct answer among the choices listed above is option B. Condensation is a process which an exothermic one. Exothermic processes involves heat being released to the environment which is evident in the process of condensation.

Sauron [17]3 years ago

3 0

Answer: The correct answer is Option B.

Explanation:

Exothermic reaction is defined as the reaction in which heat is released to the surroundings from the system. The total enthalpy change of the reaction comes out to be negative.

Endothermic reactions are the ones where heat is absorbed from the surrounding by the system. The total enthalpy change of this reaction comes out to be positive.

For the given options:

Option A: When ammonium nitrate is added in the water to cool it, the heat is getting absorbed. Then only the water is getting cooled. Thus, it is considered as an endothermic reaction.

Option B: Condensation is a process in which gaseous state changes into liquid state. The temperature of the system gets reduced and thus heat is getting released in this process. Thus, it is considered as an exothermic reaction.

Option C: Melting is a physical process in which solid state is converted into liquid state. To do this, heat must be provided to separate the particles from one another. Thus, it is considered as an endothermic reaction.

Option D: When sugar is dissolved in water, heat is provided so that it gets completely dissolved. Thus, it is considered as an endothermic reaction.

Hence, the correct answer is Option B.

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Please help!!!!its due tomorrow !!!

scZoUnD [109]

#6).
Every 1,000 mL makes 1 L
How many 1,000mL are there in 2,800 mL ?
That's division.
 (2,800 mL) / (1,000 mL) = 2.8 L

#7).
The 'perimeter' means the 'distance all the way around'.
You have to know that both sides of a rectangle are the same length,
and also the top and bottom are the same length.
So the perimeter of this rectangle is

 (2 yd) + (4.5 yd) + (2.yd) + (4.5 yd) = 13 yd .

Oops. The problem wants to know the perimeter in feet.
So you have to know that each yard is the same as 3 feet.
In order to find the number of feet in 13 yards, you have to
take 3 feet 13 times .

 (3 feet) times (13) = 39 feet .

#8).
For this one, you have to know that every 36 inches makes 1 yard.

How many 36 inches are there in 48 inches ?
That's division.
 (48 inches) / (36inches) = 1 and 1/2 yards .

#9).
For this problem, you have to know how to handle a mixed number,
and you also have to know that there are 16 ounces in 1 pound.

Add up the fruit:

 (3-1/2 pounds) + (4 pounds) + 2 pounds) = 9-1/2 pounds

Now, remember that each pound is the same as 16 ounces. So if you
want to find the number of ounces in 9-1/2 pounds, you have to take
16 ounces 9-1/2 times .

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___________________________________

#10).
This one is just adding up some numbers. But after you finish doing that, you have to know that 1,000 meters is called '1 kilometer' .

Add up the distances that Omar ran:

 (1,000 meters) + (1,625 meters) + (1,500 meters) = 4,125 meters

The problem wants to know how many kilometers this is, so you have to figure out how many '1,000 meters' fit into 4,125 meters.

That's division.

 (4,125 meters) / (1,000 meters) = 4.125 kilometers

4 0

3 years ago

In order to prepare very dilute solutions, a lab technician chooses to perform a series of dilutions instead of measuring a very

SVETLANKA909090 [29]

Answer: The final concentration of potassium nitrate is $5.70\times 10^{-6}M$

Explanation:

To calculate the molecular mass of solute, we use the equation used to calculate the molarity of solution:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in mL)}}$

We are given:

Mass of potassium nitrate (solute) = 0.360 g

Molar mass of potassium nitrate = 101.1 g/mol

Volume of solution = 500.0 mL

Putting values in above equation, we get:

$\text{Molarity of }KNO_3=\frac{0.360\times 1000}{101.1\times 500.0}\\\\\text{Molarity of }KNO_3=7.12\times 10^{-3}M$

To calculate the molarity of the diluted solution, we use the equation:

$M_1V_1=M_2V_2$ .......(1)

Calculating for first dilution:

$M_1\text{ and }V_1$ are the molarity and volume of the concentrated $KNO_3$ solution

$M_2\text{ and }V_2$ are the molarity and volume of diluted $KNO_3$ solution

We are given:

$M_1=7.12\times 10^{-3}M\\V_1=10mL\\M_2=?M\\V_2=500.0mL$

Putting values in equation 1, we get:

$7.12\times 10^{-3}\times 10=M_2\times 500\\\\M_2=\frac{7.12\times 10^{-3}\times 10}{500}=1.424\times 10^{-4}M$

Calculating for second dilution:

$M_2\text{ and }V_2$ are the molarity and volume of the concentrated $KNO_3$ solution

$M_3\text{ and }V_3$ are the molarity and volume of diluted $KNO_3$ solution

We are given:

$M_2=1.424\times 10^{-4}M\\V_2=10mL\\M_3=?M\\V_3=250.0mL$

Putting values in equation 1, we get:

$1.424\times 10^{-4}\times 10=M_3\times 250\\\\M_3=\frac{1.424\times 10^{-4}\times 10}{250}=5.70\times 10^{-6}M$

Hence, the final concentration of potassium nitrate is $5.70\times 10^{-6}M$

8 0

3 years ago

Write a balanced nuclear equation for the formation of 28 Si 14 from beta-minus emission.

Fantom [35]

Answer:

Phosphorus-28 undergoes beta-minus decay to produce

an electron,
a Silicon-28 nuclei, and
an electron antineutrino.

$\rm ^{28}_{13} Al \to ^{28}_{14} Si + ^{\phantom{-}0}_{-1}e + \bar{\mathnormal{v}}_{\rm e}$

Explanation:

In simple words, when a nucleus undergoes beta-minus decay, a neutron is converted to a proton. An electron and an electron antineutrino will be released.

$\rm ^{1}_{0}n^{0} \to ^{1}_{1}p^{+} + ^{\phantom{-}0}_{-1}e^{-} + \bar{\mathnormal{v}}_{\rm e}$ .

One way to tell whether a neutron is converted to a proton, but not vice versa, is to check the sum charges on the two sides of this equation.

Left-hand side: 0. Neutron is neutral.
Right-hand side: 1 + (-1) = 0. Each proton carries a charge of +1. Each electron (beta-minus particle) carries a charge of -1. Antineutrinos are neutral.

The charges on the two sides of this equation is the same. Hence this nuclear equation is possible (but not necessarily correct; however, if the proton and the neutron are in the wrong place the charge won't even be the same.)

Since the mass number of a proton and a neutron are both 1, the overall mass number of the atom will stay the same.

The atomic number is the number of protons in each atom. That number determines the symbol and the chemical properties of the atom. When one neutron in an atom is converted to a proton, the atomic number of the atom will increase by 1.

The atomic number of the daughter nucleus, silicon, is 14. It takes a parent nucleus with atomic number $14 - 1 = 13$ to produce a silicon atom. Refer to a modern periodic table. Atomic number $13$ corresponds to the element aluminum.

Also, the mass number of the daughter nucleus is 28. Since the mass number would stay the same in a beta decay, the mass number of the parent nucleus would also be 28. In other words, it takes an aluminum-28 atom to undergo beta-decay to produce a silicon-28 atom.

Complete the other details (electron and electron antineutrino) to obtain the equation

$\rm ^{28}_{13} Al \to ^{28}_{14} Si + ^{\phantom{-}0}_{-1}e + \bar{\mathnormal{v}}_{\rm e}$ .

6 0

3 years ago

What is the volume of 1.60 grams of O2 gas at STP? (5 points)

tiny-mole [99]

Answer:

1.12 liters

Explanation:

Calculating number of moles

Molar mass of O₂ = 32 g
n = Given weight / Molar mass
n = 1.6/32
n = 0.05 moles

At STP

One mole of O₂ occupies 22.4 L
Therefore, 0.05 moles will occupy :
22.4 L x 0.05 = 1.12 L

5 0

2 years ago

Read 2 more answers

What are the metalloids on the periodic table?

Sauron [17]

The metalloids; boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), polonium (Po) and astatine (At) are the elements found along the step like line between metals and non-metals of the periodic table.

5 0

2 years ago