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3 years ago

How do you know how to order an empirical formula?

2 answers:

8 0

Solving Empirical Formula Problems There are two common types of empirical formula problems. Luckily, the steps to solve either are almost exactly the same. Example #1: Given mass % of elements in a compound.
A compound was found to contain 32.65% Sulfur, 65.3% Oxygen and 2.04% Hydrogen. What is the empirical formula of the compound?
1) The first step in this problem is to change the % to grams.
32.65%→32.65g of S
65.3%→65.3g of O
2.04%→2.04g of H
2) Next divide all the given masses by their molar mass.
32.65g of S/ 32gm-1 = 1.0203 moles of S
65.3g of O/ 16gm-1 = 4.08 moles of O
2.04g of H/ 1.008gm-1 = 2.024 moles of H
3) Then, pick the smallest answer in moles from the previous step and divide all the answers by that. Remember that if you calculate a number that is x0.9 round to the nearest whole number
1.0203 moles of S/ 1.0203 = 1
4.08 moles of O/1.0203 = 3.998 ≈ 4
2.024 moles of H/1.0203 = 1.984 ≈ 2
4) Lastly, the coefficients calculated in the previous step will become the subscripts in the chemical formula.
S = 1
O = 4
H = 2
H2SO4
Example#2: Given the mass of a reactant before a chemical reaction and the mass of a product after a reaction.
When 0.273g of Mg is heated in a Nitrogen (N2) environment a chemical reaction occurs. The product of the reaction is 0.378g . Calculate the empirical formula.
1) In any empirical formula problem you must first find the mass % of the elements in the compound. Since the total mass of the final product was 0.378 we find that:
0.378g total-0.273g magnesium = 0.105g nitrogen
0.105g nitrogen/0.378g total (100) = 27.77%
0.273g magnesium/0.378g total (100) =72.23%
2) Then change the % to grams
27.77%→27.77g of N
72.23%→72.23g of Mg
3) Next, divide all the masses by their respective molar masses.
27.77g/14gm-1 = 1.98 moles N
72.23g/24.31gm-1 = 2.97 moles Mg

inessss [21]3 years ago

3 0

Answer:

Start with the number of grams of each element, given in the problem. the mass of each element = the percent given. Convert the mass of each element to moles using the molar mass from the periodic table. Divide each mole value by the smallest number of moles calculated.

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The oxidation of ammonia produces nitrogen and water via the following reaction: 4NH3(g) + 3O2(g) → 2N2(g) + 6H2O(l) Suppose the

Sonbull [250]

Answer:

The rate of consumption of $NH_{3}$ is 2.0 mol/L.s

Explanation:

Applying law of mass action to this reaction-

$-\frac{1}{4}\frac{\Delta [NH_{3}]}{\Delta t}=-\frac{1}{3}\frac{\Delta [O_{2}]}{\Delta t}=\frac{1}{2}\frac{\Delta [N_{2}]}{\Delta t}=\frac{1}{6}\frac{\Delta [H_{2}O]}{\Delta t}$

where $-\frac{\Delta [NH_{3}]}{\Delta t}$ represents rate of consumption of $NH_{3}$ , $-\frac{\Delta [O_{2}]}{\Delta t}$ represents rate of consumption of $O_{2}$ , $\frac{\Delta [N_{2}]}{\Delta t}$ represents rate of formation of $N_{2}$ and $\frac{\Delta [H_{2}O]}{\Delta t}$ represents rate of formation of $H_{2}O$ .

Here rate of formation of $H_{2}O$ is 3.0 mol/(L.s)

From the above equation we can write-

$-\frac{1}{4}\frac{\Delta [NH_{3}]}{\Delta t}=\frac{1}{6}\frac{\Delta [H_{2}O]}{\Delta t}$

Here $\frac{\Delta [H_{2}O]}{\Delta t}=3.0 mol/(L.s))$

So, $-\frac{\Delta [NH_{3}]}{\Delta t}=\frac{4}{6}\frac{\Delta [H_{2}O]}{\Delta t}$

Hence, $-\frac{\Delta [NH_{3}]}{\Delta t}=\frac{4}{6}\times 3.0 mol/(L.s)=2.0 mol/(L.s)$

6 0

3 years ago

Which of the following best explains why ionic crystals are brittle?

Natalka [10]

Packing

Explanation:

Ionic crystals are brittle due to the tight packing of their crystals. This provides little to no mobility between one another.

Brittleness implies having little to no elasticity.
Ionic crystals are held together by strong crystal lattice forces
These forces prevents crystals from freely rotating and moving space.
It holds them rigidly and fixed in place.
Ionic crystals are hard and held electrostatic forces.

learn more:

Ionic compounds brainly.com/question/6071838

#learnwithBrainly

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4 years ago

Ethane, C2H6, can be formed by reacting acetylene, C2H2, with hydrogen gas as follows: C2H2(g) H2(g) ⇌ C2H6(g) Exothermic What c

Pavel [41]

Answer:

Equilibrium shifts to the right

Explanation:

An exothermic reaction is one in which temperature is released to the environment. Hence, if the reaction vessel housing an exothermic reaction is touched after reaction completion, we will notice that the reaction vessel e.g beaker is hot.

To consider the equilibrium response to temperature changes, we need to consider if the reaction is exothermic or endothermic. In the case of this particular question, it has been established that the reaction is exothermic.

Heat is released to the surroundings as the reactants are at a higher energy level compared to the products. Hence, increasing the temperature will favor the formation of more reactants and as such, the equilibrium position will shift to the left to pave way for the formation of more reactants. Thus , more acetylene and hydrogen would be yielded

8 0

3 years ago

How do atoms make molecules?

bazaltina [42]

Explanation:

Atoms can join together - they form bonds together - to make MOLECULES. ... For example, a hydrogen atom forms one bond, an oxygen atom forms two, and carbon forms four bonds. Look at that molecule of water again - each hydrogen has one bond, and the oxygen in the middle has two bonds. Molecules can be much bigger.

5 0

3 years ago

Adding energy has no effect on the rate of evaporation? True or False ?

zlopas [31]

Answer:

False

Explanation:

Evaporation occurs when molecules in a liquid gain enough energy that they overcome attractions from other molecules and break away to become a gas. Adding energy increases the rate of evaporation.

Hope this helped!

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3 years ago