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3 years ago

What is the percent composition of carbon in heptane c7h16

Chemistry

1 answer:

Gnom [1K]3 years ago

8 0

Answer: the percent composition of carbon in heptane is 83.9%

Explanation:

1) Atomic masses of the atoms:

C: 12.01 g/mol

H: 1.008 g/mol

2) Molar mass of heptane:

C₇H₁₆: 7 × 12.01 g/mol + 16×1.008 g/mol = 100.2 g/mol

3) Mass of carbon in one mole of heptane:

C₇: 7 × 12.01 g/mol = 84.07 g/mol

3) Percent composition of carbon:

% = (mass in grams of C) / (mass in grams of C₇H₁₆) × 100 =

= (84.07 g/ 100.2 g) × 100 = 83.9% ← answer

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How many centimeters are in .479 kilometers

trapecia [35]

Answer:

47900 cm

General Formulas and Concepts:

Chemistry

Base 10 Decimal System
Using Dimensional Analysis

Explanation:

Step 1: Define

0.479 km

Step 2: Identify Conversions

1 km = 1000 m

1 m = 100 cm

Step 3: Convert

$0.479 \ km(\frac{1000 \ m}{1 \ km} )(\frac{100 \ cm}{1 \ m} )$ = 47900. cm

Step 4: Check

We are given 3 sig figs. Follow sig fig rules.

47900. cm ≈ 47900 cm

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2 years ago

Part C Number of molecules in 8.437x10-2 mol C6H6

N76 [4]

Answer:

There are $5.08\times 10^{22}\ \text{molecules of}\ C_6H_6$

Explanation:

In this problem, we need to find the number of molecules in $8.437\times 10^{-2}$ mol of $C_6H_6$ .

The molar mass of $C_6H_6$ is $6\times 12+1\times 6=78\ g/mol$

No of moles = mass/molar mass

We can find mass from above formula.

$m=n\times M\\\\m=8.437\times 10^{-2}\ mol\times 78\ g/mol\\\\m=6.58\ g$

Also,

No of moles = no of molecules/Avogadro number

$N=n\times N_A\\\\N=8.437\times 10^{-2}\times 6.023\times 10^{23}\\\\N=5.08\times 10^{22}\ \text{molecules}$

Hence, there are $5.08\times 10^{22}\ \text{molecules of}\ C_6H_6$

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3 years ago

Bromine has an atomic mass of 79.9 amu, but only has 2 naturally occurring isotopes, Bromine-79 and Bromine-81. If Bromine-80 do

galina1969 [7]

Educated Guess Here!

Since Br-80 does not exist, maybe that means Br-79 or Br-81 have very unequal abundances. For example, Br-79 may have 75% abundance whereas Br-81 may have 25% abundance.

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2 years ago

The ability of an atom in a molecule to attract electrons is best quantified by the ________.

nevsk [136]

Answer:

b. electronegativity

Explanation:

The ability of an atom in a molecule to attract electrons is best quantified by the _Electronegativity_.

Electronegativity is the ability of an atom to attract a shared pair of electron which is loosely held. Polar molecules often possess such properties. The Halogen group (group 17) is famous for such property because it has the highest electronegativity in periodic table.

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2 years ago

A 25.0-mL sample of 0.100M Ba(OH)2(aq) is titrated with 0.125 M HCl(aq).

morpeh [17]

Answer:

20.0

Explanation:

NaOH = (25.0) (0.100m) \ 0.125M = 20.0mL

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3 years ago