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Wewaii [24]
2 years ago
9

One mole of a metallic oxide reacts with one mole of hydrogen to produce two moles of the pure metal

Chemistry
1 answer:
Scorpion4ik [409]2 years ago
6 0

Answer:

Formulas

3.2 Determining Empirical and Molecular Formulas

Learning Objectives

By the end of this section, you will be able to:

Compute the percent composition of a compound

Determine the empirical formula of a compound

Determine the molecular formula of a compound

The previous section discussed the relationship between the bulk mass of a substance and the number of atoms or molecules it contains (moles). Given the chemical formula of the substance, one may determine the amount of the substance (moles) from its mass, and vice versa. But what if the chemical formula of a substance is unknown? In this section, these same principles will be applied to derive the chemical formulas of unknown substances from experimental mass measurements.

Percent Composition

The elemental makeup of a compound defines its chemical identity, and chemical formulas are the most succinct way of representing this elemental makeup. When a compound’s formula is unknown, measuring the mass of each of its constituent elements is often the first step in the process of determining the formula experimentally. The results of these measurements permit the calculation of the compound’s percent composition, defined as the percentage by mass of each element in the compound. For example, consider a gaseous compound composed solely of carbon and hydrogen. The percent composition of this compound could be represented as follows:

%H=mass Hmass compound×100%

%C=mass Cmass compound×100%

If analysis of a 10.0-g sample of this gas showed it to contain 2.5 g H and 7.5 g C, the percent composition would be calculated to be 25% H and 75% C:

%H=2.5g H10.0g compound×100%=25%

%C=7.5g C10.0g compound×100%=75%

EXAMPLE 3.9

Calculation of Percent Composition

Analysis of a 12.04-g sample of a liquid compound composed of carbon, hydrogen, and nitrogen showed it to contain 7.34 g C, 1.85 g H, and 2.85 g N. What is the percent composition of this compound?

Solution

To calculate percent composition, divide the experimentally derived mass of each element by the overall mass of the compound, and then convert to a percentage:

%C=7.34g C12.04g compound×100%=61.0%%H=1.85g H12.04g compound×100%=15.4%%N=2.85g N12.04g compound×100%=23.7%

The analysis results indicate that the compound is 61.0% C, 15.4% H, and 23.7% N by mass.

Check Your Learning

A 24.81-g sample of a gaseous compound containing only carbon, oxygen, and chlorine is determined to contain 3.01 g C, 4.00 g O, and 17.81 g Cl. What is this compound’s percent composition?

ANSWER:

12.1% C, 16.1% O, 71.8% Cl

Determining Percent Composition from Molecular or Empirical Formulas

Percent composition is also useful for evaluating the relative abundance of a given element in different compounds of known formulas. As one example, consider the common nitrogen-containing fertilizers ammonia (NH3), ammonium nitrate (NH4NO3), and urea (CH4N2O). The element nitrogen is the active ingredient for agricultural purposes, so the mass percentage of nitrogen in the compound is a practical and economic concern for consumers choosing among these fertilizers. For these sorts of applications, the percent composition of a compound is easily derived from its formula mass and the atomic masses of its constituent elements. A molecule of NH3 contains one N atom weighing 14.01 amu and three H atoms weighing a total of (3 × 1.008 amu) = 3.024 amu. The formula mass of ammonia is therefore (14.01 amu + 3.024 amu) = 17.03 amu, and its percent composition is:

%N=14.01amu N17.03amuNH3×100%=82.27%%H=3.024amu H17.03amuNH3×100%=17.76%

This same approach may be taken considering a pair of molecules, a dozen molecules, or a mole of molecules, etc. The latter amount is most convenient and would simply involve the use of molar masses instead of atomic and formula masses, as demonstrated Example 3.10. As long as the molecular or empirical formula of the compound in question is known, the percent composition may be derived from the atomic or molar masses of the

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When the equation 
galina1969 [7]

Answer:

The least whole number coefficient for HNO₃ is 6

Explanation:

The chemical equation above is the reaction between calcium orthophosphate and nitric acid.

To balance a chemical equation, we have to consider law of conservation of matter which states that matter can neither be created nor destroyed.

What this law implies is that, whatever we have at the reactant side must be equal to whatever is obtainable at the product side.

The above equation is

Ca₃(PO₄)₂ + HNO₃ → Ca(NO₃)₂ + H₃PO₄

To balance the equation, we'll have to check the number of atoms at each side and possibly balance the equation with the number of moles.

The balanced equation is

Ca₃(PO₄)₂ + 6HNO₃ → 3Ca(NO₃)₂ + 2H₃PO₄

From the balanced equation above, we can see that the number of calcium (Ca), Phosphorus (P), Oxygen(O), Nitrogen(N) and hydrogen (H) are balanced at both sides of the equation.

The least number coefficient for HNO₃ is 6

3 0
2 years ago
How do the interactions that are broken in water when it is boiled compare with those broken when water is electrolyzed? Boiling
nasty-shy [4]

Answer:

Boiling water breaks intermolecular attractions and electrolysis breaks covalent bonds.

Explanation:

When water boils, hydrogen bonds are broken between adjacent water molecules. The hydrogen bond is an intermolecular bond between adjacent oxygen and hydrogen atoms of water molecules.  

During electrolysis, water dissociates in the presence of electric current. Here, ions are formed in the process. Therefore, covalent bonds are broken here.

8 0
3 years ago
Name the compound formed when a copper cation that has a 2+ charge combines with a bromine anion that has a 1- charge.
Lynna [10]
The compound that is formed when a copper cation and a bromine anion reacts would be Copper (II) bromide. It will have a chemical formula CuBr2. This reaction is a synthesis reaction where two substances reacts to form one product.
6 0
3 years ago
Read 2 more answers
What is the nature of the Ca-Cl bond in a molecule of calcium chloride (CaCl2) if the electronegativity value of calcium is 1.0
nevsk [136]
Ca-Cl is an ionic bond. We know this because the difference between their electronegativities is 2.16.The electronegativity tells us which atom will attract the electron more than the other. Hence, chlorine attracts the electron a lot more than the calcium.A difference of more than 1.6 (or 1.7 depending on the source) implies that the electrons are so unevenly shared, that the bond is ionic, rather than polar covalent.

3 0
3 years ago
Calculate the number of moles of C2H6 in 6.29×1023 molecules of C2H6.
Kipish [7]

1.05moles

Explanation:

Given parameters:

Number of molecules of C₂H₆ = 6.29 x 10²³molecules

Unknown:

Number of moles = ?

Solution:

The mole is the amount of substances that contains Avogadro's number of particles i.e 6.02 x 10²³

 To find the number of moles:

  number of moles = \frac{number of particles}{Avogadro's number}

  number of moles = \frac{6.29 x 10^{23} }{6.02 x 10^{23} }

  number of moles = 1.05moles

Learn more:

moles brainly.com/question/1841136

#learnwithBrainly

7 0
3 years ago
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