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Tasya [4]
3 years ago
5

A 42.0g sample of compound containing only C and H was analyzed. The results showed that the sample contained 36.0g of C and 6.0

g of H.
Which of the following questions about the compound can be answered using the results of the analysis?

A) What was the volume of the sample?
B) What is the molar mass of the compound?
C) What is the chemical stability of the compound?
D) What is the empirical formula of the compound?
Chemistry
1 answer:
user100 [1]3 years ago
5 0

Answer:

What is the empirical formula of the compound?

Explanation:

When the relative masses of elements in a hydrocarbon are given, it is possible to use this information to obtain the empirical formula by dividing the given masses of each element by the relative atomic masses of the element. The lowest ratio is now used to divide through to obtain the empirical formula of the compound.

The empirical formula only shows that ratio of atoms of each element present in the compound. From the information provided, the empirical formula of the compound is CH2. Hence the answer.

You might be interested in
What is the mass of 0.55 mole<br> of magnesium chloride?
Gala2k [10]

Answer:

SYMBOLS, FORMULAS AND MOLAR MASSES

OBJECTIVES

1. To correctly write and interpret chemical formulas

2. To calculate molecular weights from chemical formulas

3. To calculate moles from grams using chemical formulas

INTRODUCTION

Part I. Symbols and formulas

An element is a homogeneous pure substance made up of identical atoms. All matter is made

up of elements and, since chemistry is the study of matter, it is convenient to use symbols to represent

the elements rather than using the entire name.

By international agreement, specific symbols are assigned to each element (Note: This means

that while names of the elements vary with language, symbols are constant throughout the world.) Each

element is assigned a one- or two-letter symbol. The first letter is capitalized, the second (if there is

one) is not. While this often seems trivial, it is in fact a very important point. For example, in chemical

language Co represents cobalt, which is a metal and an element, while CO represents carbon monoxide,

a compound which is a colorless, odorless gas! Even when there is not an obvious correspondence,

for instance "MN", it can cause confusion. Do you mean the element manganese? Did you forget a

letter and mean something else? Are you using "M" to represent something else entirely? Chemists

sometimes use "M" to represent any metal. It is well worth the trouble to memorize the symbols for

common elements.

Since compounds consist of elements, the chemical formulas of compounds also consist of

elements with subscripts used to denote the number of atoms per molecule. If there is no subscript, it is

implied that there is one of that kind of atom. Ones never appear in chemical formulas. Not only do

subscripts denote ratios of atoms, they also denote the ratio of moles of element to one mole of

compound. Parentheses can be used to show groups of atoms, with the subscripts showing how many

groups there are. Parentheses are not used if there is only one group.

Examples: For one mole of the following compounds, how many moles of each element are

present?

MgCl2 1 mole Mg, 2 moles Cl

Mg(NO3)2 1 mole Mg, 2 moles N, 6 moles O

NaNO3 1 mole Na, 1 mole N, 3 mole O

AgCl 1 mole Ag, 1 mole ClPart II. Molar Masses

Each atom has a different size and therefore a different mass. The relative masses of each

element can be found on the periodic table. For example, one atom of magnesium weighs 24.31 amu

(atomic mass units). However, one mole of magnesium weighs 24.31 g. (Moles were planned that

way!) Since one mole of MgCl2 consists of one mole of magnesium and two moles of chlorine, the

mass of one mole of MgCl2 must be the sum of the masses of the elements. The mass of one mole of a

substance is called the molar mass or molecular weight.

Examples: What is the molar mass of the following compounds?

MgCl2 24.31 + 2(35.45) = 95.21 g/mol

Mg(NO3)2 24.31 + 2(14.01) + 6(16.00) = 148.33 g/mol

NaNO3 23.00 + 14.01 + 3(16.00) = 85.01 g/mol

AgCl 107.9 + 35.45 = 143.4 g/mol

(Note: Yes! You DO have to count significant figures when calculating molecular weight/molar

mass. However, the number of significant figures may vary depending on which periodic table you use.)

Chemists are generally interested in number of moles. Unfortunately, it is impossible to measure

moles directly. However, masses are easily measured, and if the chemical formula of the compound is

known, the molar mass can be used to determine the number of moles. The molar mass is defined as:

molar mass = grams/moles = g/mol (1)

Moles may be calculated by using molar mass as a conversion factor in dimensional analysis where

molar mass in grams = 1 (exactly) mole of compound (2)

This method is used in multi-step calculations. For example, if 0.873 g of MgCl2 is weighed out, it

is 9.17 x 10-3

moles.

1 mole

0.873g x 95.21 g = 9.17 x 10-3

mol MgCl2 (3)

However, 0.873 g of AgCl is only 6.09 x 10-3

mol.

1 mole

0.873g x 143.4 g = 6.09 x 10-3

mol AgCl (4)Molar mass may also be used to relate moles to grams. For example, 0.158 mol of MgCl2 is 15.2 g.

0.158 mol x 95.21 g = 15.2 g MgCl2 (5)

1 mol

Percent is used to express parts per one hundred. Usually in chemistry, it refers to

g of species of interest x 100 = % (6)

g of whole thing

Example: For the % Mg in MgCl2: In one mole of MgCl2, there are 24.31 g of Mg (molar mass of Mg,

the part we are interested in) and 95.21 g of MgCl2 (the whole thing), so %Mg in MgCl2 is

(24.31/95.21) x 100 = 25.53% Mg (7)

PROCEDURE

Work individually.

The formula for calcium phosphate is Ca3(PO4)2. Weigh about 2 g of calcium phosphate to the

nearest 0.001 g. In other words, you do not have to have exactly 2.000g, but you must know the

weight you have exactly. Acceptable results include but are not limited to: 1.985g , 2.035g, 2.314g

etc.

Be sure to report all results with the correct number of significant figures and appropriate units!

5 0
3 years ago
_________ is a systematic method of naming chemical compounds. This creates an unambiguous and consistent name for any chemical
Vlada [557]

Answer: IUPAC NOMENCLATURE

Explanation:

IUPAC stands for International Union of Pure and Applied Chemistry. They devised a systematic method for naming compounds in order to create a uniform global unambiguous system of nomenclature hence making it easier for researchers to share information more freely without the hindrance of reporting the same compound using different names in different parts of the world thus creating confusion in chemical literature.

6 0
3 years ago
Al + Fe2O3 → Al2O3 + Fe (Need to balance equation)
andriy [413]
20.7 g of Fe can be produced with 10.0g of Al

6 0
3 years ago
How do I solve the following word problem: The half-life of Phosphorus - 32 is 14.3 days. It is used to study a plant's use of f
BaLLatris [955]

Half life is the time that it takes for half of the original value of some amount of a radioactive element to decay.

We have the following equation representing the half-life decay:

A=A_o\times2^{(-\frac{t}{t_{half}})_{}_{}}

A is the resulting amount after t time

Ao is the initial amount = 50 mg

t= Elapsed time

t half is the half-life of the substance = 14.3 days

We replace the know values into the equation to have an exponential decay function for a 50mg sample

A=\text{ 50 }\times2^{\frac{-t}{14.3}}

That would be the answer for a)

To know the P-32 remaining after 84 days we have to replace this value in the equation:

\begin{gathered} A=\text{ 50 }\times2^{\frac{-84}{14.3}} \\ A=0.85\text{ mg} \end{gathered}

So, after 84 days the P-32 remaining will be 0.85 mg

4 0
1 year ago
Which action most likely causes large rocks to become smaller pieces of rock?
algol13

Answer:B

Explanation:

7 0
3 years ago
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