Oxygen has a total of 8 electrons, does that satisfy the octet rule? Explain why or why not.

Which rule for assigning oxidation numbers is correct?

LenKa [72]

Hydrogen is usually –1. This is INCORRECT. The oxidation number for H is +1.
Oxygen is usually –2. This is CORRECT.
A pure group 1 element is +1. This is INCORRECT. It does not follow. This will depend on the other elements and the overall charge.
A monatomic ion is 0. This is INCORRECT. Diatomic ion is 0.

4 0

3 years ago

Read 2 more answers

In science, we like to develop explanations that we can use to predict the outcome of events and phenomena. Try to develop an ex

Kay [80]

The question is incomplete. The complete question is :

In science, we like to develop explanations that we can use to predict the outcome of events and phenomena. Try to develop an explanation that tells how much NaOH needs to be added to a beaker of HCl to cause the color to change. Your explanation can be something like: The color change will occur when [some amount] of NaOH is added because the color change occurs when [some condition]. The goal for your explanation is that it describes the outcome of this example, but can also be used to predict the outcome of other examples of this phenomenon. Here's an example explanation: The color of the solution will change when 40 ml of NaOH is added to a beaker of HCl because the color always changes when 40ml of base is added. Although this explanation works for this example, it probably won't work in examples where the flask contains a different amount of HCl, such as 30ml. Try to make an explanation that accurately predicts the outcome of other versions of this phenomenon.

Solution :

Consider the equation of the reaction between NaOH and $HCl$

NaOH (aq) + HCl (aq) → NaCl(aq) + $H_2O (l)$

The above equation tells us that $1 \text{mole}$ of $NaOH$ reacts with $1 \text{mole}$ of $HCl$ .

So at the equivalence point, the moles of NaOH added = moles of $HCl$ present.

If the volume of the $HCl$ taken = $V_1$ mL and the conc. of $HCl$ = $M_1$ mole/L

The volume of NaOH added up to the color change = $V_2 \text{ and conc of NaOH = M}_2$ mole/L

Moles of $HCl$ taken = $V_1 \ mL \times M_1 \ mol/100 \ mL = V_2M_2 \times 10^{-3}$ moles.

The color change will occur when the moles of NaOH added is equal to the moles of $HCl$ taken.

Thus when $V_1 M_1 \times 10^{-3} = V_2M_2 \times 10^{-3}$

or when $V_1M_1 = V_2M_2$

or $V_2=\frac{V_1M_1}{M_2}$ mL of NaOH added, we observe the color change.

Where $V_1, M_1$ are the volume and molarity of the $HCl$ taken.

$M_2$ is the molarity of NaOH added.

When both the NaOH and $HCl$ are of the same concentrations, i.e. if $M_1=M_2$ , then $V_2=V_1$

Or the 40 mL of $HCl$ will need 40 mL of NaOH for a color change and

30 mL of $HCl$ would need 30 mL of NaOH for the color change (provided the concentration $M_1=M_2$ )

7 0

3 years ago

Moles/Mass/Molecules Practice Problem Worksheet

Komok [63]

Answer:

Explanation:

1) Convert 11.03 moles of calcium nitrate to grams.

Given data:

Number of moles = 11.03 mol

Mass of calcium nitrate = ?

Solution:

Formula:

Number of moles = mass / molar mass

Now we will rearrange the formula because we have to calculate the mass.

Mass = number of moles × molar mass

Molar mass of calcium nitrate = 164.088 g/mol

Mass = 11.03 mol × 164.088 g/mol

Mass = 1809.89 g

2. How many molecules are contained in 103.4g of sulfuric acid?

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

Given data:

Number of molecules = ?

Mass of sulfuric acid = 103.4 g

Solution:

Formula:

Number of moles = mass / molar mass

Number of moles = 103.4 g/ 98.079 g/mol

Number of moles = 1.05 mol

1 mole = 6.022 × 10²³ molecules

1.05 mol × 6.022 × 10²³ molecules / 1mol

6.323 × 10²³ molecules of sulfuric acid

3. 3.25 x 1024 molecules of dinitrogen pentoxide would be how many moles?

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

Given data:

Number of molecules of dinitrogen pentoxide = 3.25 × 10²⁴

Moles of dinitrogen pentoxide = ?

Solution:

1 mole = 6.022 × 10²³ molecules

1 mol × 3.25 × 10²⁴ molecules / 6.022 × 10²³ molecules

5.4 moles

4. What would be the mass of 9.03 x 1021 molecules of hydrobromic acid?

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

Given data:

Number of molecules of hydrobromic acid = 9.03 × 10²¹

Mass of hydrobromic acid = ?

Solution:

First of all we will calculate the moles of hydrobromic acid.

1 mole = 6.022 × 10²³ molecules

1 mol × 9.03 × 10²¹ molecules / 6.022 × 10²³ molecules

0.015 moles

Mass of hydrobromic acid:

Mass = number of moles × molar mass

Mass = 0.015 mol × 80.9 g/mol

Mass =1.21 g

5. A sample of iron (III) chloride has a mass of 26.29g. How many moles would this be?

Given data:

Number of moles =?

Mass of iron(III) chloride = 26.29 g

Solution:

Formula:

Number of moles = mass / molar mass

Molar mass of iron chloride = 162.2 g/mol

Now we will put the values in formula.

Moles = 26.29 g/ 162.2 g/mol

Moles = 0.16 g

6 0

3 years ago

Consider the reaction:

murzikaleks [220]

Answer: The formation of given amount of oxygen gas results in the absorption of 713 kJ of heat.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of oxygen gas = 83 g

Molar mass of oxygen gas = 32 g/mol

Putting values in above equation, we get:

$\text{Moles of oxygen gas}=\frac{83g}{32g/mol}=2.594mol$

For the given chemical equation:

$2Fe_2O_3\rightarrow 4Fe+3O_2;\Delta H^o_{rxn}=+824.2kJ$

Sign convention of heat:

When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.

By Stoichiometry of the reaction:

When 3 moles of oxygen gas is formed, the amount of heat absorbed is 824.2 kJ

So, when 2.594 moles of oxygen gas is formed, the amount of heat absorbed will be = $\frac{824.2kJ}{3mol}\times 2.59mol=713kJ$

Hence, the formation of given amount of oxygen gas results in the absorption of 713 kJ of heat.

7 0

3 years ago

Explain why are hydrogen and oxygen considered as wheares water as a compound?

Elina [12.6K]

Hydrogen and oxygen are different elements.

when two or more elements combine, they form a compound

hence, two molecules of hydrogen and one molecule of oxygen combine to form water as a compound

3 0

3 years ago