Help answer these chemistry questions

Help Answer These Chemistry Questions

Answers

Answer 1

Answer:

45th answer is pure and properties 42 is periodictable


Related Questions

Heat transfer takes place when:
A. there is a temperature difference.
B. conduction or convection occurs, but not radiation.
OC. thermal energy is present.
D. None of these

Answers

Answer:

A. There is a temperature difference

Explation:

Whenever there is a temperature difference, heat transfer occurs. Heat transfer may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice chest.

Answer:

A.) there is a temperature difference

Explanation:

I got it correct on founders edtell

A sample of gas occupies 1.2 L at 12.0oC. Assuming pressure remains the same, what would be the volume (in L) of this gas at 67oC?

A.
1.4

B.
1.0

C.
0.2

D.
5.0

E.
6.7

Answers

Answer:

e.

6.7

hope it help

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Color of the CuCl2 hydrate before heating:

Answers

hydrated cucl2 have blue-green colour

Under certain conditions, the substance mercury(II) oxide can be broken down to form mercury and oxygen. If 24.1 grams of mercury(II) oxide react to form 22.3 grams of mercury, how many grams of oxygen must simultaneously be formed? Grams oxygen

Answers

Answer:

1.76 g

Explanation:

2HgO(s) ==> 2Hg(l) + O2(g)

Number of moles of Hg = 22.3 g/ 201g/mol

= 0.11 moles

From the reaction equation;

2 moles of Hg is formed alongside 1 mole of oxygen

Hence;

0.11 moles of Hg forms 0.11 moles × 1/2

= 0.055 moles of oxygen

Mass of oxygen formed = 0.055 moles of oxygen × 32g/mol = 1.76 g

4. Magnesium is the limiting reactant in this experiment. Calculate the theoretical yield of MgO for each trial.

5. Determine the percent yield of MgO for your experiment for each trial.

6. Determine the average percent yield of MgO for the two trials.

Answers

Answer: The average percent yield of MgO is 98.59 %.

Explanation:

The chemical equation follows:

[tex]2Mg(s)+O_2(g)\rightarrow 2MgO(s)[/tex]

For Trial 1:

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of Mg = 0.411 g

Molar mass of Mg = 24.3 g/mol

Plugging values in equation 1:

[tex]\text{Moles of Mg}=\frac{0.411g}{24.3g/mol}=0.0170 mol[/tex]

By the stoichiometry of the reaction:

If 2 moles of Mg produces 2 moles of MgO

So, 0.0170 moles of Mg will produce = [tex]\frac{2}{2}\times 0.0170=0.0170mol[/tex] of MgO

We know, molar mass of [tex]MgO[/tex] = 40.3 g/mol

Putting values in equation 1, we get:

[tex]\text{Mass of }MgO=(0.0170mol\times 40.3g/mol)=0.685g[/tex]

The percent yield of a reaction is calculated by using an equation:

[tex]\% \text{yield}=\frac{\text{Actual value}}{\text{Theoretical value}}\times 100[/tex] ......(2)

Given values:

Actual value of the product = 0.675 g

Theoretical value of the product = 0.685 g

Plugging values in equation 1:

[tex]\% \text{yield}=\frac{0.675g}{0.685g}\times 100\\\\\% \text{yield}=98.54\%[/tex]

Hence, the % yield of the product is 98.54 %

For Trial 2:

Given mass of Mg = 0.266 g

Molar mass of Mg = 24.3 g/mol

Plugging values in equation 1:

[tex]\text{Moles of Mg}=\frac{0.266g}{24.3g/mol}=0.011 mol[/tex]

By the stoichiometry of the reaction:

If 2 moles of Mg produces 2 moles of MgO

So, 0.011 moles of Mg will produce = [tex]\frac{2}{2}\times 0.011=0.011mol[/tex] of MgO

We know, molar mass of  = 40.3 g/mol

Putting values in equation 1, we get:

[tex]\text{Mass of }MgO=(0.011mol\times 40.3g/mol)=0.443g[/tex]

The percent yield of a reaction is calculated by using an equation:

[tex]\% \text{yield}=\frac{\text{Actual value}}{\text{Theoretical value}}\times 100[/tex] ......(2)

Given values:

Actual value of the product = 0.437 g

Theoretical value of the product = 0.443 g

Plugging values in equation 1:

[tex]\% \text{yield}=\frac{0.437g}{0.443g}\times 100\\\\\% \text{yield}=98.64\%[/tex]

Hence, the % yield of the product is 98.64 %

Average of a measurement is calculated by given formula:

[tex]Average=\frac{M_1+M_2}{2}[/tex]

where,

[tex]M_1[/tex] = percentage yield for Trial 1 = 98.54 %

[tex]M_2[/tex] = percentage yield for Trial 2 = 98.64 %

Putting values in above equation, we get:

[tex]Average=\frac{98.54+98.64}{2}=98.59\%[/tex]

Hence, the average percent yield of MgO is 98.59 %.

What amount of SeC16 is needed to produce 4.45 mol of chlorine gas in the
reaction Seclo +0 218) —SeO, +3Cl2te)?
2.85 mol
0.95 mol
5.70 mol
8.55 mol
1.49 mol

Answers

Answer:

1.48 moles of SeCl6 are needed

Explanation:

Based on the reaction:

SeCl6 + O2 → SeO2 + 3Cl2

1 mole of SeCl6 reacts producing 3 moles of Cl2.

To solve this question we need to use the conversion factor:

1mol SeCl6 = 3mol Cl2

As we want to produce 4.45 moles of Cl2, we need:

4.45 mol Cl2 * (1mol SeCl6 / 3mol Cl2) =

1.48 moles of SeCl6 are needed

A 100 g sample of potassium chlorate, KCIO3(s), is completely decomposed by heating:
2 KCIO3(s) 2 KCl(s) + 3 O2(g)
The oxygen is collected at 89 kPa and 23°C. Calculate the volume, in litres, of oxygen that would be
produced during the decomposition of this sample.

Answers

Explanation:
In order to be able to calculate the volume of oxygen gas produced by this reaction, you need to know the conditions for pressure and temperature.
Since no mention of those conditions was made, I'll assume that the reaction takes place at STP, Standard Temperature and Pressure.
STP conditions are defined as a pressure of
100 kPa
and a temperature of
0

C
. Under these conditions for pressure and temperature, one mole of any ideal gas occupies
22.7 L
- this is known as the molar volume of a gas at STP.
So, in order to find the volume of oxygen gas at STP, you need to know how many moles of oxygen are produced by this reaction.
The balanced chemical equation for this decomposition reaction looks like this
2
KClO
3(s]
heat
×
−−−→
2
KCl
(s]
+
3
O
2(g]



Notice that you have a
2
:
3
mole ratio between potassium chlorate and oxygen gas.
This tells you that the reaction will always produce
3
2
times more moles of oxygen gas than the number of moles of potassium chlorate that underwent decomposition.
Use potassium chlorate's molar mass to determine how many moles you have in that
231-g
sample
231
g

1 mole KClO
3
122.55
g
=
1.885 moles KClO
3
Use the aforementioned mole ratio to determine how many moles of oxygen would be produced from this many moles of potassium chlorate
1.885
moles KClO
3

3
moles O
2
2
moles KClO
3
=
2.8275 moles O
2
So, what volume would this many moles occupy at STP?
2.8275
moles

22.7 L
1
mol
=
64.2 L

e) Hydrogen gas is a non-metal and can be prepared in a laboratory Explain why hydrogen gas is collected over water.​

Answers

Answer:

to collect pure hydrogen and avoid mixing with air

HELP PLEASE 15 POINTS

The rate law for a reaction is found to be rate = k[X]4. By what factor does the rate increase if [X] is doubled?

Answers

X is doubled by 5 and xk is in the fa

Which equation describes a physical change? i. H2O(s) ⟶ H2O(l) ii. Na+(aq)+Cl−(aq) +Ag+(aq)+NO3−(aq) ⟶ AgCl(s)+Na+(aq)+NO3−(aq) iii. CH3OH(g)+O2(g) ⟶ CO2(g)+H2O(g) iv. 2H2O(l) ⟶ 2H2(g)+O2(g) v. H+(aq)+OH−(aq)⟶ H2O(l)

Answers

Answer:

The answer is "Option i"

Explanation:

In this question, only option (i) is correct, and others were wrong which can be defined as follows:

In option (ii):

[tex]Na^+\ (aq)+Cl^- \ (aq) +Ag^+ \ (aq)+NO_3^- \ (aq) \to AgCl\ (s)+Na^+ \ (aq)+NO_3^-\ (aq) \\\\[/tex]

It is the complete ionic equation.

In option (iii):

[tex]CH_3OH\ (g)+O_2\ (g) \to CO_2\ (g)+H_2O\ (g)[/tex]

It is the combustion reaction but a not balanced equation.

In option (iv):

[tex]2H_2O\ (l) \to 2H_2\ (g)+O_2\ (g)[/tex]

It is the  decomposition equation.

In option (v):

[tex]H^+\ (aq) +OH^-\ (aq)\to H_2O\ (l)[/tex]

It is the complete ionic equation.

what is the reactant(s) in the chemical equation below

3CO(g) + Fe2O3(s) 2Fe(s) + 3CO2(g)

Answers

Answer:

the reactants are carbon dioxide ,iron, oxygen

The dehydration of a secondary alcohol, like cyclohexanol, is a mechanism that occurs Choose... . First, the alcohol is protonated to Choose... , creating Choose... intermediate. Then, a Choose... is removed, moving the electrons from that bond to make a Choose... bond.

Answers

Answer:

Mechanism

explanation:

have a great day!

What is the atomic number of the atom in the diagram above please ?

Answers

Answer:

5

Explanation:

The atomic number is the number of protons in an atom. Protons are the positively charged particles in the nucleus. The number of protons define the identity of an element. An element with 5 protons is Boron, no matter how many neutrons may be present.

The atomic number of the atom shown in the diagram is 5.

What is the atomic number?

The atomic number of an element refers to the number of protons in the nucleus of its atoms. It uniquely identifies an element and determines its chemical properties.

In the diagram, there are 5 proton numbers in the nucleus of the atom. In other words, this means that the atomic number of the atom is 5.

More on atomic numbers can be found here: https://brainly.com/question/14190064

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How can you calculate the instantaneous rate of a reaction from a graph of concentrations over time?

Answers

by calculating the negative of the slope of the curve of concentration of a reactant versus time at time t.
by calculating the slope of the curve of concentration of a product versus time at time t.

PLZ HELP ME WITH MY WORK
How many different elements are there in the molecule C8H11NO2,?
A. 21
B. 2
c. 11
D. 4 ​

Answers

Answer:

option C 11

is the correct answer

By which process aqua fortis is manufactured
1) Haber's process
2) Ostwald process
3) Contact process
4) Deacon's process​

Answers

Answer: Aqua fortis is also known as Nitric Acid  

Explanation: and the process in making aqua fortis is THE OSTWALDS PROCESS

detailed explanation by me

ammonia is also used in this process, which is reacted with oxygen and water and a catalyst platinum.

HOPE THIS HELPSS!!!

Any individual offspring produced through a sexual reproduction is always,

Answers

Answer:

Any individual offspring produced through asexual reproduction is always: genetically identical to its parent. made up of cells with a cell wall. different from all of its siblings

Any individual offspring produced through asexual reproduction is always: genetically identical to its parent. made up of cells with a cell wall. different from all of its siblings

Water is super soluble and this solubility is incredibly helpful for life. Tell me how this solubility helps maintain different processes when it comes to life.

Answers

Answer: Water is SUPER soluble and regarded as an universal solvent because it is polar in nature and dissolves most inorganic solutes and some polar organic solutes to form aqueous solutions.

Explanation:

WATER is a substance which is composed of the elements such as hydrogen and oxygen that are combined in the ratio of 2:1. The physical properties of water include:

--> it is a colourless, odourless and tasteless liquid and

--> the boiling point of water is 100°C(this is due to the presence of hydrogen bonding).

The solubility of a solute in a solvent at a particular temperature is the maximum amount of solute in moles or grams that will saturate 1000 dm³ or grams of the solvent.

Water is regarded as a universal solvent BECAUSE it is capable of dissolving many substances. This solubility helps maintain different processes in life such as acting as the solvent which helps cells transport and use substances like oxygen or nutrients.

2.
In photosynthesis, which substances are used up, which are produced and which are necessary
but remain unchanged after the reaction?
used up
produced
remain
A
carbon dioxide
water
oxygen
A
8
chlorophylt
carbon dioxide
water
с
oxygen
starch
cellulose
D
water
oxygen
chlorophyll

Answers

D. Water is used up, Oxygen is produced and Chlorophyll is necessary, but remains unchanged.


Which of these solutions is acidic?

Answers

Answer:

Option a is a solution acidic ([OH⁻] = 7.0x10⁻⁹ M).

Explanation:

To know if a solution is acidic we need to calculate the pH and it must be lower than 7. A value of pH equal to 7 is a neutral solution and a solution with a pH value higher than 7 is a basic solution.

a. For the [OH⁻] = 7.0x10⁻⁹ M we have:

[tex] pOH = -log[OH^{-}] = -log(7.0 \cdot 10^{-9}) = 8.15 [/tex]

Now, the pH is:

[tex] pH + pOH = 14 [/tex]

[tex] pH = 14 - pOH = 14 - 8.15 = 5.85 [/tex]

This solution is acidic (pH < 7)

b. [H₃O⁺] = 8.5x10⁻⁸ M

[tex] pH = -log(8.5 \cdot 10^{-8}) = 7.07 [/tex]

This is not an acidic solution. Is a neutral one (pH around to 7).

c. [OH⁻] = 2.5x10⁻⁶ M

[tex] pOH = -log[OH^{-}] = -log(2.5 \cdot 10^{-6}) = 5.60 [/tex]

Then, the pH is:

[tex]pH = 14 - pOH = 14 - 5.60 = 8.40[/tex]

Hence, this is not an acidic solution. It is basic (pH > 7).    

Therefore, option a is a solution acidic ([OH⁻] = 7.0x10⁻⁹ M).

I hope it helps you!

Elements in the same period Question 7 options: A) form bonds with the same type of elements. B) have the same number of protons. C) have the same number of valence electrons. D) have the same principal quantum number.

Answers

D is the answer .. I have send u pic also

ASAP
Which of the following describes a characteristic of water that makes it cohesive in nature?

A - It has a partial negative charge on hydrogen and a partial positive charge on oxygen.
B - It has a linear molecular structure with H-O-H arranged in a straight line.
C - It has a vast electronegativity difference between its constituent atoms.
D - It requires a high amount of heat to raise or drop its temperature.

Answers

The answer is C.

The vast difference in electronegativity of the oxygen and hydrogen in water, the O-H bond is polar.

The characteristic of water that makes it cohesive in nature is that It has a vast electronegativity difference between its atoms. So, option C is correct one.

Why water is cohesive in nature?

The water molecule contains two hydrogen atoms and oxygen atom.

The electronegativity of hydrogen atoms and oxyegen atom is 2.1 and 3.44

Due to high electronegativity of oxygen ,it can attract the bonded pair of electron of hydrogen and form a strong bond and make it cohesive in nature.

What are major characteristics of water?

The water molecule have unique characteristics among all some are given below.

Water is polar, with partial positive charge on two hydrogen and partial negative charge on one oxygen.

Water is act as solvent and dissolves the polar and ionic substance.Water has high heat of vaporization.Water has cohesive and adhesive properties.Water has high heat capacity.

learn about water molecule Here,

brainly.com/question/26529979

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The number of grams of helium in a balloon at a pressure of 99.8 kPa, a temperature of 301 K, and a volume of 0.785 L would be

Options:

814 g

0.125 g

0.278 g

337 g

Answers

use formula
pV=nRT
in formula n=m/M
you have to find m



P=99.8/101.325
v=0.785
R=0.0821
T=301

The number of grams of helium in a balloon at a pressure of 99.8 kPa, a temperature of 301 K, and a volume of 0.785 L would be 0.125g.

How to calculate mass?

The mass of a substance can be calculated by multiplying the number of moles by its molar mass.

However, the number of moles of helium must be calculated as follows:

PV = nRT

Where;

P = pressureV = volumen = no of molesR = gas law constantT = temperature

0.985 × 0.785 = n × 0.0821 × 301

0.773 = 24.7n

n = 0.773 ÷ 24.7 = 0.031moles

mass of He = 0.031 × 4 = 0.125g

Therefore, the number of grams of helium in a balloon at a pressure of 99.8 kPa, a temperature of 301 K, and a volume of 0.785 L would be 0.125g.

Learn more about mass at: https://brainly.com/question/19694949

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why is unit of pressure called a derived unit ?? 2) how do you measure the volume of milk?

Answers

1. Unit of pressure called a derived unit because it is a combination of base units (kg·m^-1·s^·2).

2. We measure the volume of milk by a instrument called Milk Lactometer.

An example of basic research is A) the development of new plastics that can be recycled. B) the study of the relationship between the amount of automobile emissions gases in the atmosphere and the decomposition of atmospheric ozone. C) the study of the composition of the atom. D) the design of new batteries for electric cars. E) the study of natural compounds in sea animals to look for new molecules that can be used for medicine.

Answers

Answer:

C) the study of the composition of the atom.

Explanation:

A research can be defined as a systematic investigation or careful consideration of study with respect to a particular problem using scientific methods such as collection of data, documenting critical information, analysis of data, and the establishment of facts in order to reach new conclusions.

Similarly, a basic research is an approach to research that's typically theoritical and it's aimed at developing a theory, searching for the truth or gain a better understanding about a phenomenon, subject, or basic laws on nature.

In this context, an example of basic research is the study of the composition of the atom.

An atom can be defined as the smallest unit comprising of matter that forms all chemical elements. Thus, atoms are basically the building blocks of matters and as such determines or defines the structure of a chemical element.

Generally, atoms are typically made up of three distinct particles and these are protons, neutrons and electrons.

balanced chemical equation:Copper( ii) oxide solid +dilute sulphuric acid​

Answers

Answer:

CuO + H2SO4 = CuSO4 + H2O  

Reaction type: double replacement

PLZ HELP What human body system includes the stomach, intestines, and teeth?
A. Respiratory system
B. Digestive system
C. Skeletal system
D. Muscular system SUBMIT​

Answers

Answer:

B

Explanation:

the digestive system

Plz help I will give brainliest

Answers

Answer:

1. Fr

2. cl

3.H20

4.2 mole

5. 3

6. c

Organisms do not adapt as a result of competition for resources.

Answers

Answer:

The given statement is False.

The organisms adapt as a result of competition for resources. Different places have different organisms suited for that particular places.

The animals living at a particular place compete for the resources available and the nature selects the organism that has won the competition for resources.

The organisms are evolved as a result of competition for resources

Answer:

I just wanted to say the other person is totally right.

this statement is false.

What effect does temperature have on reaction rate?
A. An increase in temperature does not change the reaction rate,
B. An increase in temperature keeps the reaction from stopping.
C. An increase in temperature speeds up the reaction rate.
D. An increase in temperature slows the reaction down.

Answers

The answer for this multiple choice question is C



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