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Alex_Xolod [135]
3 years ago
7

4. The heat of

Chemistry
1 answer:
Reika [66]3 years ago
8 0

It is 2 KJ

It is because the formula is :

q=m∆Hf

where m is the mass and ∆Hf is the heat fusion.

So, we get:

q=80×25

q=2000J or 2 KJ

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During which step in the pcr cycle do primers form bonds with a single-stranded template?.
shutvik [7]
Answer: The first steps

Explanation: science
5 0
3 years ago
A solution is prepared by dissolving 15 grams of sugar in 85 grams of water. How many percent of sugar is in the solution?
trasher [3.6K]

Answer:

15%

Explanation:

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

Mass of sugar = 15 g

Mass of water = 85 g

Percentage of sugar in the solution =?

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

Mass of solute (sugar) = 15 g

Mass of solvent (water) = 85 g

Mass of solution =?

Mass of solution = mass of solute + mass of solvent

Mass of solution = 15 + 85

Mass of solution = 100 g

Finally, we shall determine the percentage of the sugar in the solution. This can be obtained as follow:

Mass of solute (sugar) = 15 g

Mass of solution = 100 g

Percentage of sugar in the solution =?

Percentage = solute /solution × 100

Percentage = 15 / 100 × 100

Percentage of sugar in the solution = 15%

7 0
3 years ago
A solution is prepared by mixing 100 mL of 1 M HCl and 250 mL of 5 M NaCl. What is the total volume of the solution?
olga55 [171]

Answer:

<u></u>

  • <u>350 mL</u>

Explanation:

Normally, in the neutralization reactions, that is how the reactions between and acid and a base are called, you assume additive volumes.

Additive volumes means that the <em>volume</em> of the final <em>solution</em> is equal to the sum of the separate volumes of the two solutions that are mixed.

It is not totally accurate, but it is a good approximation and for lack of additional data it is what is used.

Then, assuming additive volumes:

  • Total volume of the solution = 100 mL + 250 mL = 350 mL.
8 0
4 years ago
Give the following reaction: ammonium nitrate—&gt; dinitrogen monoxide + water.
Vladimir [108]

Answer:

a) NH₄NO₃ ⇒ N₂O + 2 H₂O

b) 1.69 × 10²³ molecules

Explanation:

Step 1: Write the balanced equation

NH₄NO₃ ⇒ N₂O + 2 H₂O

Step 2: Convert 11.2 g of NH₄NO₃ to moles

The molar mass of NH₄NO₃ is 80.04 g/mol.

11.2 g × 1 mol/80.04 g = 0.140 mol

Step 3: Calculate the moles of H₂O produced

0.140 mol NH₄NO₃ × 2 mol H₂O/1 mol NH₄NO₃ = 0.280 mol H₂O

Step 4: Calculate the number of molecules in 0.280 moles of water

We will use Avogadro's number.

0.280 mol × 6.02 × 10²³ molecules/1 mol = 1.69 × 10²³ molecules

6 0
3 years ago
Which formula represents a
Gre4nikov [31]

Answer:

A. H2O

Explanation:

Let us first define the three types of bonds:

1. Nonpolar Covalent: electronegativity difference < 0.4

2. Polar Covalent: electronegativity difference between 0.4 and 1.8

3. Ionic: electronegativity difference > 1.8

This will help us eliminate choices C and D:

-NaCl has a electronegativity difference of 3.0 - 0.9 = 2.1 (ionic bond)

-Cl2 has a electronegativity difference of 3.0 - 3.0 = 0 (nonpolar covalent bond)

However, we still have two more options, A and B, but they are not diatomic for us to use the electronegativity differences with.

We must now consult their geometries. Because CO2 has a linear geometry (O=C=O), the two sides will cancel each other out, resulting in a nonpolar covalent bond. At this point, by process of elimination, we can already determine the answer to be A. H2O. We can verify this by looking at the geometry of H2O, which is bent (H-O-H; imagine the O is above the H's, I cannot draw it in this response). H2O's bent geometry classifies it as polar covalent; the electrons are slightly more attracted towards the O, the more electronegative element. Side note: this makes the O slightly more negative in charge, whilst the H's are slightly more positive in charge.

P.S. I apologize for not being able to draw and demonstrate that last paragraph, but I hope you get a general idea. You can search up the "H2O geometry" and "CO2 geometry" to get a better idea! :)

8 0
3 years ago
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