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3 years ago

Classify the reactions as endothermic or exothermic....PLEASE HELP ASAP

Chemistry

1 answer:

elena55 [62]3 years ago

4 0

1) Endothermic reactions:

a) The reaction between ammonium nitrate and water absorbs heat from the surrounding environment.

There are two types of reaction: endothermic reaction (chemical reaction that absorbs more energy than it releases) and exothermic reaction (chemical reaction that releases more energy than it absorbs).

b) Ammonium chloride dissolved in a beaker of water makes the beaker cold.

Dissolving this salt absorbs heat from beaker.

c) Water separates on hydrogen and oxygen when an electric current is run through it.

Electrolysis of water is the decomposition reaction (heat is required), because from one molecule (water) two molecules (hydrogen and oxygen) are produced. Water is separated into two molecules.

2) Exothermic reactions:

a) Three drops of concetrated sulfuric acid added to 100 milliliters in a beaker makes the beaker hot.

Energy is released, beaker absorbs that heat.

b) Uranium atoms are split to produce nuclear energy.

Nuclear energy is released.

c) Methane and oxygen are combined to produce methanol and heat.

Balanced chemical reaction: 2CH₄ + O₂ → 2CH₃OH + heat.

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I need to make up an experiment !! Please help

katen-ka-za [31]

Question: Baking a Cake Without Flour.

Hypothesis: I think that when I remove the flour from the standard cake recipe, I'll end up with a flat but tasty cake.

Procedure: I baked two cakes during my experiment. For my control, I baked a cake following a normal recipe. I used the Double Fudge Cake recipe on page 292 of the Betty Crocker Cookbook. For my experimental cake, I followed the same recipe but left out the flour. I first obtained a 2-quart mixing bowl.

Results: My control cake, which I cooked for 25 minutes, measured 4 cm high. Eight out of ten tasters that I picked at random from the class found it to be an acceptable dessert. After 25 minutes of baking, my experimental cake was 1.5 cm high and all ten tasters refused to eat it because it was burnt to a crisp.

What did I learn?/Conclusion: Since the experimental cake burned, my results did not support my hypothesis. I think that the cake burned because it had less mass, but cooked for the same amount of time. I propose that the baking time be shortened in subsequent trials.

I hope this helped :))

7 0

3 years ago

What would cause the equilibrium to shift left in this reaction? CO + 3H2 ? CH4 + H2O A. Adding heat to the product mixture B. A

Irina-Kira [14]

Answer:

Pretty sure the answer is A on Plato

Explanation:

I looked it up, and it said that raising the temperature would cause the equilibrium to shift left.

8 0

3 years ago

Read 2 more answers

Liquid hexane

maks197457 [2]

Answer: The mass of $H_2O$ produced is 2.52 g

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(1)

For hexane:

Given mass of hexane = 1.72 g

Molar mass of hexane = 86.18 g/mol

Putting values in equation 1, we get:

$\text{Moles of hexane}=\frac{1.72g}{86.18g/mol}=0.020mol$

For oxygen gas:

Given mass of oxygen gas = 8.0 g

Molar mass of oxygen gas= 32 g/mol

Putting values in equation 1, we get:

$\text{Moles of water}=\frac{8.0g}{32g/mol}=0.25mol$

The chemical equation for the combustion of hexane follows:

$2C_6H_{14}+19O_2\rightarrow 12CO_2+14H_2O$

By stoichiometry of the reaction:

If 2 moles of hexane reacts with 19 moles of oxygen gas

So, 0.020 moles of hexane will react with = $\frac{19}{2}\times 0.020=0.19mol$ of oxygen gas

As the given amount of oxygen gas is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.

Thus, hexane is considered a limiting reagent because it limits the formation of the product.

By the stoichiometry of the reaction:

If 2 moles of hexane produces 14 moles of $H_2O$

So, 0.020 moles of hexane will produce = $\frac{14}{2}\times 0.020=0.14mol$ of $H_2O$

We know, molar mass of $H_2O$ = 18 g/mol

Putting values in above equation, we get:

$\text{Mass of }H_2O=(0.14mol\times 18g/mol)=2.52g$

Hence, the mass of $H_2O$ produced is 2.52 g

4 0

3 years ago

Fill in the blanks below.

Elenna [48]

Answer:

Explanation:

6CO₂ + 6 H₂O ⇄ C₆H₁₂0₆ + 6O₂

This is the chemical equation given .

1. The equation shows a __Chemical equation_______the breaking and forming of chemical bonds that leads to a change in the composition of matter.

2. In the equation, CO₂ is a___reactant_____.

3. In the equation, C₆H₁₂0₆ is a ___product________.

4. In O₂, the type of bond that holds the two oxygen atoms together is a_nonpolar_covalent bond_________.

5. In H₂O, the type of bond that holds one of the hydrogen atoms to the oxygen atom is a__polar_hydrogen bond____.

6. The number of oxygen atoms on the left side of the equation is__equal to_________ the number of oxygen atoms on the right side.

5 0

3 years ago

Using your knowledge of chemistry and the information in Reference Table H, which statement concerning propanone and water at 50

stiv31 [10]

The answer is (2) higher vapor pressure and weaker intermolecular forces. Propanone has a lower boiling point, so it is more volatile than water. Propanone's vapor pressure is, therefore, higher than that of water at 50 degrees Celsius. Propanone is more volatile due to the fact that the intermolecular forces that hold its molecuels together are not as strong as those that hold together molecules of water. Since the IMFs are weaker, it takes less thermal energy to break individual molecules free of each other.

3 0

3 years ago