What did the periodic table help scientists discover?

Based upon the following equation: P4 + 5 O2 --> 2 P2O5 How many grams of P4 (molar mass 124 g = 1 mole) are necessary to rea

choli [55]

Sorry I don't know this

4 0

2 years ago

How do you draw the structure of 5-iodo-2-methoxyhexane?

monitta

The structure is in attachment.
Hexane is alkane (acyclic saturated hydrocarbon, carbon-carbon bonds are single) of six carbon atoms. Methoxy group is the functional group consisting of a methyl group bound to oxygen. Iodo is substituent consists of ionide (element in 17 periodic group).

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8 0

2 years ago

Read 2 more answers

Match the words to the definitions below.

puteri [66]

Answer:

Explanation:

1. Turns litmus paper blue, taste bitter, donate OH- ions, feel slippery, 8-14 on pH scale.

BASE

BASE: A base is a substance that reacts with water to yield excess hydroxide ions.

Some of its characteristics are:

>It has a bitter taste

>Their aqeuos solutions have a soapy feel

>They have a PH greater than 7

>They turn red litmus paper blue

>They are electrolytes

2. The amount of ions per an amount of solvent. Ex: 10g salt/100g water

CONCENTRATION

Concentration is the amount of solute that can be found in a solution.

3. A lab procedure to deliver a measured volume of solution, generally measured in ml.

TITRATION

Titration is a laboratory procedure that is used to determine the amount of solution that is needed to drive a reaction to completion. It involves adding a solution to a known volume of another solution.

4. A substance or solution that resists changes in pH by stabilizing hydrogen ion concentration.

BUFFER

A buffer is solution that is made up of weak acids and their salts or weak bases and their salts. Such solutions are able to resist changes in PH

5. Turns litmus paper red, taste sour, donate H+, corrode metals, 0-6 on pH scale.

ACID

An acid is a proton donor, hydrogen ions.

Characteristics:

>Acids turns blue litmus paper red, they have sour taste and easily corrodes metals.

>They have a PH value between 0-6 on the scale.

>They are generally electrolytes

6. Logarithmic scale to indicate the amount of hydrogen ions in solution.

PH SCALE

A PH scale is a logarithmic scale that runs from 1-14 and is used to indicate the amount of hydrogen ions in a solution.

7. A chemical (dye created from lichens) that changes color in response to changes in pH.

LITMUS PAPER

Litmus paper is made of dyes created from lichen and it changes its color as PH changes. Acids turns blue litmus paper red while bases changes the color of litmus to blue from red. Litmus test is a popular test for solutions.

8. Acids and bases are added proportionally and result in a chemical reaction that causes the pH of a solution to reach pH 7.

NEUTRALIZATION

Neutralization is the reaction of acids and bases to produce salts and water. The endpoint of neutralization reaction signifies the point at which equal number of bases neutralizes an acid. The PH is 7 at this point.

5 0

3 years ago

A compound is 7.74% hydrogen and 92.26% carbon by mass. At 100°C a 0.6883 g sample of the gas occupies 250 mL when the pressure

ycow [4]

Answer: The molecular formula for the compound is $C_6H_6$

Explanation:

We are given:

Percentage of C = 92.26 %

Percentage of H = 7.74 %

Let the mass of compound be 100 g. So, percentages given are taken as mass.

Mass of C = 92.26 g

Mass of H = 7.74 g

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{92.26g}{12g/mole}=7.68moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{7.74g}{1g/mole}=7.74moles$

Step 2: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 7.68 moles.

For Carbon = $\frac{7.68}{7.68}=1$

For Hydrogen = $\frac{7.74}{7.68}=1$

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H = 1 : 1

The empirical formula for the given compound is $CH$

Calculating the molar mass of the compound:

To calculate the molecular mass, we use the equation given by ideal gas equation:

PV = nRT

Or,

$PV=\frac{m}{M}RT$

where,

P = pressure of the gas = 820 torr

V = Volume of gas = 250 mL = 0.250 L (Conversion factor: 1 L = 1000 mL )

m = mass of gas = 0.6883 g

M = Molar mass of gas = ?

R = Gas constant = $62.3637\text{ L. torr }mol^{-1}K^{-1}$

T = temperature of the gas = $100^oC=(100+273)K=373K$

Putting values in above equation, we get:

$820torr\times 0.250L=\frac{0.6883g}{M}\times 62.3637\text{ L torr }mol^{-1}K^{-1}\times 373K\\\\M=\frac{0.6883\times 62.3637\times 373}{820\times 0.250}=78.10g/mol$

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is:

$n=\frac{\text{Molecular mass}}{\text{Empirical mass}}$

We are given:

Mass of molecular formula = 78.10 g/mol

Mass of empirical formula = 13 g/mol

Putting values in above equation, we get:

$n=\frac{78.10g/mol}{13g/mol}=6$

Multiplying this valency by the subscript of every element of empirical formula, we get:

$C_{(1\times 6)}H_{(1\times 6)}=C_6H_6$

Hence, the molecular formula for the compound is $C_6H_6$

8 0

3 years ago

If a flask maintained at 674 K contains 0.138 moles of NH4I(s) in equilibrium with 4.34×10-2 M NH3(g) and 9.39×10-2 M HI(g), wha

r-ruslan [8.4K]

Answer:

K = 4.07x10⁻³

Explanation:

Based on the reaction:

NH₄I(s) ⇄ NH₃(g) + HI(g)

You can define K of equilibrium as the ratio of concentrations of reactants and products, thus:

K = [NH₃] [HI] / [NH₄I]

But, as NH₄I is a solid, is not taken into account in the equilibrium, that means K expression is:

K = [NH₃] [HI]

As the concentrations in equilibrium of the gases is:

[NH₃] = 4.34x10⁻²M

[HI] = 9.39x10⁻²M

Equilibrium constant, K, is:

K = 4.34x10⁻²M * 9.39x10⁻²M

4 0

2 years ago