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3 years ago

Explain the difference between endothermic and exothermic processes. Provide an example of each.

Chemistry

1 answer:

Talja [164]3 years ago

3 0

<h3>Exothermic reactions </h3>

These are reactions that transfer energy to the surroundings (ie the energy exits from the reaction, hence the name exothermic). The energy is usually transferred as heat energy, causing the reaction mixture and its surroundings to become hotter. A thermometer is used to detect the temperature increase.

Examples:

Combustion

Neutralisation between acids and alkali

<h3>Endothermic reactions </h3>

These are reactions that take in energy from the surroundings (ie energy enters the reaction, which will help you to remember the name endothermic). The energy is usually transferred as heat energy, causing the reaction mixture and its surroundings to become colder. A thermometer is used to detect the temperature decrease.

Example:

Electrolysis

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3. Given 20g of Barium Hydroxide, how many grams of

anastassius [24]

The number of grams of ammonium nitrate (NH₄NO₃) it would take for all the barium hydroxide to react is 18.7g

First, we will write the balanced chemical equation for the reaction

The balanced chemical equation for the reaction is

Ba(OH)₂ + 2NH₄NO₃ → 2NH₄OH + Ba(NO₃)₂

This means, 1 mole of barium hydroxide is required to react with 2 moles of ammonium nitrate

Now, we will calculate the number of moles of barium hydroxide present.

Mass of barium hydroxide (Ba(OH)₂) = 20 g

Using the formula

$Number\ of\ moles = \frac{Mass}{Molar\ mass}$

Molar mass of Ba(OH)₂ = 171.34 g/mol

∴ Number of moles of Ba(OH)₂ present = $\frac{20}{171.34}$

Number of moles of Ba(OH)₂ present = 0.116727 mole

Now,

Since 1 mole of barium hydroxide is required to react with 2 moles of ammonium nitrate

Then,

0.116727 mole of barium hydroxide will react with 2 × 0.116727 mole of ammonium nitrate

2 × 0.116727 = 0.233454 mole

∴ Number of moles of NH₄NO₃ required is 0.233454 mole

Now, for the mass of ammonium nitrate (NH₄NO₃) required

From the formula

Mass = Number of moles × Molar mass

Molar mass of NH₄NO₃ = 80.043 g/mol

∴ Mass of NH₄NO₃ required = 0.233454 × 80.043

Mass of NH₄NO₃ required = 18.68636 g

Mass of NH₄NO₃ required ≅ 18.7g

Hence, the number of grams of ammonium nitrate (NH₄NO₃) it would take for all the barium hydroxide to react is 18.7g

Learn more on determining mass of reactant required here: brainly.com/question/11232389

6 0

2 years ago

How many grams of oxygen gas are contained in a 15 L sample at 1.02 atm and 28°C? Please show your work.

vampirchik [111]

Answer:

0.019 g.

Explanation:

Firstly, we need to find the no. of moles of oxygen gas:

We can use the general law of ideal gas: <em>PV = nRT. </em>

where, P is the pressure of the gas in atm (P = 1.02 atm).

V is the volume of the gas in L (V = 15.0 L).

n is the no. of moles of the gas in mol (n = ??? mol).

R is the general gas constant (R = 0.0821 L.atm/mol.K),

T is the temperature of the gas in K (T = 28°C + 273 = 301.0 K).

∴ n = PV/RT = (1.02 atm)(15.0 L)/(0.0821 L.atm/mol.K)(301.0 K) = 0.62 mol.

To find the mass of oxygen gas, we have:

<em>no. of moles = mass/molar mass.</em>

∴ mass of oxygen = (no. of moles)(molar mass) = (0.62 mol)(32.0 g/mol) = 0.019 g.

4 0

4 years ago

Which term is used to describe the reactant that is used up completely and controls the amount of product that can be produced d

givi [52]

Answer: Option (c) is the correct answer.

Explanation:

A limiting reagent is defined as a reagent that completely gets consumed in a chemical reaction. A limiting reagent limits the formation of products.

For example, we have given 5 mol of A and the reaction is $2A + 4B \rightarrow 2AB$

Whereas when 4 mol B will react with 2 mol of A. Hence, 8 mol of B will react with 4 mol A as follows.

$\frac{2}{4} \times 8$ = 4 mol

As, the given moles of A is more than the required moles. Thus, it is considered as an excess reagent.

Hence, B is a limiting reagent because it limits the formation of products.

Thus, we can conclude that limiting reactant is the term used to describe the reactant that is used up completely and controls the amount of product that can be produced during a chemical reaction.

6 0

4 years ago

Water is a polar molecule, meaning the electrons that are shared between the atoms aren't shared equally so oxygen attracts more

amm1812

Answer:

Magnet with a positive and a negative pole

Explanation:

A great analogy to demonstrate what a polar molecule looks like is to imagine a magnet. A magnet has one positively charged end and one negatively charged end, two poles, that is.

Imagine that we have a magnet of a shape of a prism (water molecule has a bent shape). The two base vertices of the face of the triangle are positively charged, that's because hydrogen is less electronegative than oxygen and, hence, the two hydrogen atoms are partially positively charged in a water molecule.

Oxygen is more electronegative than hydrogen meaning it has a greater electron-withdrawing force, so electrons are closer to oxygen within the O-H bonds. Oxygen, as a result, becomes partially negatively charged, so it's our negative pole of the magnet.

4 0

3 years ago

What is the percent oxygen in Rb2Cr2O7

blondinia [14]

Answer:

28.9452

Explanation:

8 0

3 years ago

Read 2 more answers