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Morgarella [4.7K]
3 years ago
5

PLEASE ANSWER True or False: When adding reactions together to get a desired reaction you must also add their enthalpies to get

the enthalpy of that desired reaction.
Chemistry
1 answer:
wariber [46]3 years ago
7 0

Answer:

true

Explanation:

You might be interested in
Molarity of 0.50 mol sugar in 270 mL of solution.
EastWind [94]
<h3>Answer:</h3>

1.85 M

<h3>Explanation:</h3>

<u>We are given;</u>

  • Number of moles as 0.50 mol
  • Volume of the solution is 270 ml

But, 1000 mL = 1 L

  • Thus, volume of the solution is 0.27 L

We are required to calculate the molarity of the solution;

  • Molarity refers to the concentration of a solution in moles per liter.
  • It is calculated by dividing number of moles with the volume.

Molarity = Moles ÷ Volume

In this case;

Molarity = 0.50 moles ÷ 0.27 L

             = 1.85 Mol/L or 1.85 M

Therefore, molarity of the solution is 1.85 M

5 0
3 years ago
Here is the electron configuration for Magnesium. How many total electrons are in the 2nd energy level?
balandron [24]

Answer:

8 electrons

Explanation:

Magnesium is present on group 2.

It has 2 valence electrons.

Electronic configuration of magnesium:

Mg₁₂ = 1s² 2s² 2p⁶ 3s²

1st energy level contain 2 electrons.(1s²)

2nd energy  level contain 8 electrons. (2s² 2p⁶)

3rd energy level contain 2 electrons. (3s²)

3rs energy level of magnesium is called valence shell. It contain two valance electrons. Magnesium can easily donate its two valance electrons and get stable electronic configuration.

It react with halogens and form salt. For example,

Mg + Cl₂   →   MgCl₂

7 0
3 years ago
A meteor falls toward Earth's surface. Given that the acceleration due to
ICE Princess25 [194]

Answer:

E = 147000  J

Explanation:

Given that,

The mass of meteor, m = 50 kg

The altitude of the meteor, h = 300 m

We need to find the potential energy of the meteor. The formula for the potential energy is given by :

E=mgh

Put all the values,

E=50\times 9.8\times 300\\\\E=147000\ J

So, the required potential energy is equal to 147000  J.

4 0
3 years ago
Match the following names of glassware with what you would use them for.
Valentin [98]

Answer:

A) Graduated pipette – Glassware used to accurately transfer small volumes.

B) Volumetric pipette – Glassware used to accurately transfer a small, single volume.

C) Beaker – Glassware best used when greater access to the contents is needed.

D) Buret – Glassware used to deliver a volume not known in advance.

E) Erlenmeyer flask – Glassware used to prevent splashing or evaporation.

F) Volumetric flask – Glassware used to make accurate solutions.

Explanation:

Graduated pipette – Glassware used to accurately transfer small volumes.

A graduated pipette is a pipette, which has a scale that shows its volume marked along the tube. It is used to transfer small volumes accurately.

Volumetric pipette – Glassware used to accurately transfer a small, single volume.

A volumetric pipette is a pipette, which has a ring like marking that is its calibrated volume. So it is used to transfer a single and small volume only. This pipette is used in volumetric analysis.

Beaker – Glassware best used when greater access to the contents is needed.

Beaker is the most widely used glassware in the laboratory. They are used to transfer large volume with less accuracy. They are of different sizes depends on the size of volumes ranging from 10 mL to 1000 mL.

Buret – Glassware used to deliver a volume not known in advance.

Buret is the most important glassware in the quantitative analysis. It has a glass tube with scale which measures the volume and a stopcock at one end from which the solvent is dispersed. It is used to measure the volume of the liquid during the titration in the quantitative analysis.

Erlenmeyer flask – Glassware used to prevent splashing or evaporation.

The most common names of Erlenmeyer flask are conical flask and titration flask. This flask has flat bottom, conical body and cylindrical neck which prevent splashing and evaporation. This flask is used in the titration process in the quantitative analysis. The solvent from the buret is delivered into the conical flask during the titration process.

Volumetric flask – Glassware used to make accurate solutions.

The volumetric flask is also an important glassware in the analytical laboratory. It is used to prepare standard solutions. It is a flask which has a ring like marking that is its calibrated volume. The mentioned volume of volumetric flask is calibrated to have accurate volume.

3 0
3 years ago
A 1.68 g sample of water is injected into a closed evacuated 5.3 liter flask at 65°C. What percent (by mass) of the water will b
Angelina_Jolie [31]

Answer:

50.4 % of the water will be vapor

Explanation:

<u>Step 1:</u> Data given

Mass of water = 1.68 grams

volume of the flask = 5.3 L

Temperature = 65°C

Vapor pressure of water at 65°C = 187.5 mmHg = 0.2467 atm

<u>Step 2:</u> Calculate moles of H2O

p*V=n*R*T

⇒ p = the pressure of water = 0.2467 atm

⇒ V = the volume of the flask = 5.3 L

⇒ n = moles of water

⇒ R = gas constant = 0.08206 L*atm/ K*mol

⇒ T = the temperature = 65°C = 338 Kelvin

n = (p*V)/(R*T)

n = (0.2467 * 5.3) /(0.08206* 338)

n = 0.047 moles

<u>Step 3:</u> Calculate mass of water

Mass of water = moles of water * molar mass of water

Mass of water = 0.047 moles *18.02 g/mol

Mass of water = 0.84694 grams

<u>Step 4:</u> Calculate the percent of water vaporized

% = (0.84694 grams/1.68 grams) *100%

% = 50.4%

50.4 % of the water will be vapor

5 0
3 years ago
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