PLEASE HELP WILL GIVE BRAINLIEST

Answer:

Number of moles = 0.057 × 10⁻⁷  mol

Explanation:

Given data:

Mass of SiO₂ = 3.4 × 10⁻⁷ g

Number of moles = ?

Solution:

Number of moles = mass/molar mass

Molar mass of SiO₂ = 60 g/mol

by putting values,

Number of moles =  3.4 × 10⁻⁷ g / 60 g/mol

Number of moles = 0.057 × 10⁻⁷  mol

Answer:

Mendeleev's greatest contribution to science is certainly the Periodic Table of Elements, which says the properties of basic elements repeat periodically when they are arranged by their atomic number. He made the discovery in 1869 during his work on the award-winning textbook on chemistry basics.

Inventions: Periodic table, Pyrocollodion

Explanation:

*Hope this helps*

Answer:

Mendeleev's greatest contribution to science is certainly the Periodic Table of Elements, which says the properties of basic elements repeat periodically when they are arranged by their atomic number. He made the discovery in 1869 during his work on the award-winning textbook on chemistry basics.

Inventions: Periodic table, Pyrocollodion

Explanation:

Answer:

The hair color of a person

Explanation:

The correct answer would be the hair color of a person.

Qualitative data are data that cannot be measured with any instrument but can only be used to characterize. Unlike quantitative data, these kinds of data can only be observed and recorded but cannot be assigned numerical values, except if coded.

The sound of a person's voice can be quantitative on one hand and qualitative on the other. The intensity of a sound can be measured using a decibel meter and quantitatively assigned a figure, whereas, the quality of the sound can only be characterized and not measured.

Both the weight and the body temperature of a person can be measured using a weighing balance and a thermometer respectively and hence, are considered to be quantitative data when collected.

The color of the hair of a person cannot be measured but can only be observed and characterized. Hence, hair color data constitute qualitative data.

Answer:

hair color

Explanation:

ANSWER;

1s22s22p63s23p63d64s2

EXPLANATION;

Molecular orbital diagram for Fe.

In writing the electron configuration for Iron the first two electrons will go in the 1s orbital. Since 1s can only hold two electrons the next 2 electrons for Iron go in the 2s orbital. The next six electrons will go in the 2p orbital. The p orbital can hold up to six electrons. We'll put six in the 2p orbital and then put the next two electrons in the 3s. Since the 3s if now full we'll move to the 3p where we'll place the next six electrons. We now shift to the 4s orbital where we place the remaining two electrons. After the 4s is full we put the remaining six electrons in the 3d orbital and end with 3d6.

Therefore the Iron electron configuration will be 1s22s22p63s23p64s23d6.

Note that when writing the electron configuration for an atom like Fe, the 3d is usually written before the 4s. Both of the configurations have the correct numbers of electrons in each orbital, it is just a matter of how the electronic configuration notation is written

Therefore we have 1s22s22p63s23p63d64s2

Answer: scientific explanation

Explanation:

A really good scientific explanation should do two main things: It should explain all the observations and data we have. It should allow us to make testable predictions that we can check using future experiments.

Explanation:

Intermolecular forces are electrostatic in nature and include van der Waals forces and hydrogen bonds. ... The three major types of intermolecular interactions are dipole–dipole interactions, London dispersion forces (these two are often referred to collectively as van der Waals forces), and hydrogen bonds.May 20, 2018

Answer:

I will give them advice, that do the power of flame low....

Explanation:

thanks.

Answer:

A and D then I guess

Explanation:

sorry hope this helps!

Answer:

54g of O2 reacted in the reaction

Answer:

54g

Explanation:

Answer:

12.3 L

Explanation:

Now we have that the rate of diffusion of the saturated hydrocarbon is R1

Rate of diffusion of sulphur dioxide is R2

Molar mass of hydrocarbon is M1

Molar mass of sulphur dioxide is 64 gmol-1

From Graham's law;

R1/R2 = √64/M1

2/1 =√64/M1

(2/1)^2 = (√64/M1)^2

4/1 = 64/M1

4M1 =64

M1 = 16

To obtain the number of moles of the gas;

(n*12) + (2n + 2) 1 = 16

12n + 2n + 2 = 16

14n + 2 = 16

14n = 16 - 2

n = 14/14

n = 1

Hence the hydrocarbon is CH4

Volume occupied by CH4 at STP = 22.4 L

Hence;

P1 = 1 atm

T1 = 273 K

V1 = 22.4 L

T2 = 300 K

P2 = 2 atm

V2 = ?

P1V1/T1 = P2V2/T2

P1V1T2 = P2V2T1

V2 = P1V1T2/P2T1

V2 = 1 * 22.4 * 300/2 * 273

V2 = 12.3 L

The volume occupied by the hydrocarbon at 27 °C and 2 atm is 12.31 L

Let the hydrocarbon be initially at standard temperature and pressure (STP)

Thus, we can obtain the new volume of the hydrocarbon by using the combined gas equation as illustrated below:

P₁V₁ / T₁ = P₂V₂ / T₂

(1 × 22.4) / 273 = (2 × V₂) / 300

22.4 / 273 = (2 × V₂) / 300

Cross multiply

273 × 2 × V₂ = 22.4 × 300

546 × V₂ = 6720

Divide both side by 546

V₂ = 6720 / 546

V₂ = 12.31 L

Thus, the volume occupied by the hydrocarbon at 27 °C and 2 atm is 12.31 L

Learn more about gas laws:

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Answer:

5

Explanation:

An alkyl group is a functional group that contains only hydrogen and carbon atoms. It has the general formula: CnH2n+1.

Since n=2, plug it into the formula.

C2H2(2)+1

=

C₂H₅

Hope that helps.

Answer:

H:H

Explanation:

Answer:

4. b 5.C

Explanation:

Photosynthesis makes sugar for plants and sunlight is the energy used to convert CO2 and water into glucose

The product of the process of photosynthesis is sugar and the energy to dive the process of photosynthesis comes from sunlight.

Photosynthesis is defined as a process by which plants and other photosynthetic organisms convert the light energy in to chemical energy  through the process of cellular respiration.

Some of the energy which is converted  is stored in molecules of carbohydrates like sugar and starches  which are made up of from carbon dioxide and water . Photosynthetic organisms which can perform photosynthesis  are algae and cyanobacteria. Photosynthesis is largely responsible for producing and maintaining the content of oxygen in earth's atmosphere.

The process begins with proteins absorbing light energy  which are called reaction centers and contain a green pigment which is called chlorophyll . In plants ,these pigments are present inside organelles called chloroplasts while in bacteria they are present in plasma membrane.

Learn more about photosynthesis,here:

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Answer: A. Kinetic energy increases during exothermic changes and decreases during endothermic changes

Explanation: During an exothermic change potential energy is converted to kinetic energy. I hope this is correct. :)

Answer:

C

Explanation:

40567⁰ kkkkkkkkkkkkkkkkkkkkkkmeow

Explanation:

cuz I got a 100

Answer:D

Explanation:

Your skin makes vitamin D

Your skin prevents dehydration

And your skin maintains body temperature. So you are left with D

Answer:

The correct option is D.

works with bones to help you move

Explanation:

Skin is the outer layer of the body and it is the body's largest organ.

It protect the body from heat and other harmful substances.

It is comprises of three layers;

The Epidermis which is the outer layer.

The dermis which is a fibrous later that protect the Epidermis.

The subcutis is the subcutaneous layer that is beneath the dermis.

Function of the skin.

1. It's regulate body temperature

2. It's protect the body from heat and pathogenic entry.

3. It produces vitamin D

4. The skin allow sensations or feelings of touch, heat, and cold.

Therefore;

works with bones to help you move is wrong because it is the muscle that work with the bone.

The concentration of iron used in the titration : 0.009 M

Given

Reaction

Cr₂O₇²⁻ + 6Fe²⁺ + 14H⁺ ⇒ 2Cr³⁺ + 6Fe³⁺ + 7H₂O

0.0093 mol/L potassium  dichromate

200 cm³ of dilute acid, 25cm³   was used in the titration.

Required

the concentration of iron

Solution

Titration formula

C₁V₁n₁=C₂V₂n₂⇒ From equation : n₁=6n₂(1=Cr₂O₇, 2=Fe)

titration average : 33+32.05+32.15+32.1 / 4 = 32.325 cm³(ml)

25 cm³ of iron solution used in titration :

[tex]\tt V_1=32.325~ml\\\\V_2=25~ml\\\\C_1=0.0093~M\\\\\\\\C_1.V_1.n_2=C_2.V_2.n_1\\\\0.0093\times 32.325\times 6=C_2\times 25\times 1\\\\C_2=0.07215~M[/tex]

Dilution(25 ml from 200 ml iron solution)

[tex]\tt C_2.V_2=C_1.V_1\\\\0.007215\times 25=C_1\times 200\\\\C_1=0.009~M[/tex]

Answer:

D

Explanation:

i learned this in elementary

Answer:

27 days, 7 hours and 43 minutes.

Explanation:

To complete a full orbit around Earth, it takes 27 days, 7 hours and 43 minutes for the Moon. This is called sidereal month and is measured by the Moon's position relative to distant *fixed" stars.

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\[/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{4 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 6.644518...[/tex]

We have the final answer as

Hope this helps you

Answer:

Yes

Explanation:

Text me on here

Answer:

A

Explanation:

Took at test on this and my teacher said it was right, hopefully I remembered right, also I answered ur other question like this I think lol

Answer:

1

1

1

1

Explanation:

the equation is balancing

The sentences that probably comes from a work of classic literature are:

The great literary works of Greek, Roman, and other prehistoric civilizations are referred to as classical literature. Classical literature includes the writings of Homer, Ovid, and Sophocles. The phrase isn't just applicable to books. It can also incorporate other types of writing, such as epic, lyric, tragedy, comedy, and pastoral.

Classical literature enables us to take a profound plunge into the lives, worldviews, and mindsets of individuals we have never met, to travel to unfamiliar settings, and to comprehend eras we will never be able to experience ourselves.

Therefore, option C and D are correct.

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Answer: Molar mass=28.224g/mol, The gas could be Nitrogen gas

Explanation:

Density is calculated as  Molar mass/ Molar Volume

Recall that

One mole of an ideal gas at (STP) standard temperature and pressure = 22.4 liters (in Volume)

Given That Density =1.26 g/L

Volume = 22.4L at STP,

Molar mass = Density x Molar Volume

= 1.26 g/L x 22.4L =28.224g

Therefore, if  1  mole of this gas has a mass of 28.224g  then  its molar mass is equal to 28.224g/mol

The molar mass of Nitrogen =  28.014 g/moL, so we can conclude the the gas could be Nitrogen

Answer:

Sentences are where there is a beginning and an end of a section of a paragraph. Letters are individual parts of sentences.

The answer that would make the MOST sense would be SENTENCES