Which of the following statement best defines matter?

Answer: CH4

Explanation:

BRAINLESS PLEASE

Answer:

O₂

Explanation:

The example of the compound or the molecule that forms a non-polar bond is oxygen gas.

Oxygen gas has a formula of O₂

Answer:D

Explanation:I did it on study island.

Radio waves are not used to generate medical images because as per the electromagnetic spectrum ,the radio waves  carry little energy that they pass through most atoms without interaction.

The electromagnetic spectrum consists of  radiation  which consists of waves made up of electromagnetic field which are capable of propogating through space and carry the radiant electromagnetic energy.

The radiation are composed of electromagnetic waves which are synchronized oscillations of electric and magnetic fields . They are created due to change which is periodic in electric as well as magnetic fields.

In vacuum ,all the electromagnetic waves travel at the same speed that is with the speed of air.The position of an electromagnetic wave in an electromagnetic spectrum is characterized by it's frequency or wavelength.They are emitted by electrically charged particles which undergo acceleration and subsequently interact with other charged particles.

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Answer:

Hey! I'll help you.

Explanation:

I got your back.

Answer:

A: melting point and the other one is i think element

Answer:

A circle graph, or a pie chart, is used to visualize information and data. A circle graph is usually used to easily show the results of an investigation in a proportional manner. Bar graphs are used to compare things between different groups or to track changes over time. However, when trying to measure change over time, bar graphs are best when the changes are larger.

Explanation:

In short, bar graphs are better to keep track of data over long periods of time, and circle graphs are better when you are trying to visualize a specific set of data.

Circle graph can be also be called pie chart, which  is more widely used. It is usually made up of a circle, divided into parts or pies. In the divided parts, it is used to differentiate between different data.

Bar charts on the other hand are like graphs having both x and y axis. It is used to represent data with respect to the height of the graph. Each data is divided into different smaller parts on the graph.

Example of what they look like is attached below.

First one is bar chart while the second is a circle graph

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Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

[tex]volume = \frac{mass}{density} \\[/tex]

From the question we have

[tex]volume = \frac{3.50}{5.61} \\ = 0.6238859...[/tex]

We have the final answer as

Hope this helps you

Answer:

Explanation:

The change in internal energy (ΔΕ) of a system : -8 kJ

The laws of thermodynamics 1 state that: energy can be changed but cannot be destroyed or created  

The equation is:  

 [tex]\tt \Delta U=Q+W[/tex]

Energy owned by the system is expressed as internal energy (U)  

This internal energy can change if it absorbs heat Q (U> 0), or releases heat (U <0). Or the internal energy can change if the system does work or accepts work (W)  

The sign rules for heat and work are set as follows:  

• The system receives heat, Q +  

• The system releases heat, Q -  

• The system does work, W -  

• the system accepts work, W +  

5 kJ of work is done on the system : W = +5 kJ

releases 13 kJ of energy to the surroundings : Q = -13 kJ

[tex]\tt \Delta E=-13+5=-8~kJ[/tex]

Answer:

Kr

Explanation:

The noble gas that is isoelectronic with Br⁻ is krypton.

This is because krypton is the closest noble gas to Br on the periodic table.

Electronic configuration of Bromine is;

            2, 8, 18, 7

  Br⁻ becomes;  2, 8, 18, 8

  Krypton is;       2, 8, 18, 8

Answer:

[tex]M_{acid}=0.08892M[/tex]

Explanation:

Hello!

In this case, since the reaction between arsenic acid and potassium hydroxide is:

[tex]H_3AsO_4+3KOH\rightarrow K_3AsO_4+3H_2O[/tex]

Thus, since the mole ratio between the acid and the base is 1:3, at the equivalence point we can write:

[tex]3n_{acid}=n_{base}[/tex]

That in terms of molarities and volumes is:

[tex]3M_{acid}V_{acid}=M_{base}V_{base}[/tex]

Thus, the concentration of the arsenic acid is:

[tex]M_{acid}=\frac{M_{base}V_{base}}{3V_{acid}}=\frac{0.1894M*35.21mL}{3*25.00mL} \\\\M_{acid}=0.08892M[/tex]

Best regards!

The concentration (M) of arsenic acid in a solution of 25.00 mL is 0.088M.

Molarity of any solution will be calculated as:

M = n/V, where

V = volume

n is the moles and it will be calculated as:
n = W/M, where

W = given mass

M = molar mass

Given chemical reaction is:

H₃AsO₄ + 3KOH → K₃AsO₄ + 3H₂O

Moles of 35.21 mL of 0.1894 M KOH will be calculated as:

n = (0.1894)(0.035) = 0.0066 moles

From the stoichiometry of the reaction it is clear that:

1 mole of H₃AsO₄ = react with 3 moles of KOH

0.0066 moles of KOH = react with 1/3×0.0066= 0.0022 moles of H₃AsO₄

Now we calculate the molarity of H₃AsO₄ in 25mL of solution as:

M = 0.0022/0.025 = 0.088 M

Hence, required molarity is 0.088 M.

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Answer:

The immune system responds to antigens by producing cells that directly attack the pathogen, or by producing special proteins called antibodies. Antibodies attach to an antigen and attract cells that will engulf and destroy the pathogen. The main cells of the immune system are lymphocytes known as B cells and T cells.

Answer:

A. The equilibrium shifts to the right, to form more products.

Explanation:

When sodium fluoride, NaF, is added to an aqueous solution, some HF is produced:

NaF + H₂O ⇄ OH⁻ + Na⁺ + HF.

That is, some H⁺ reacts decreasing its concentration.

Now, the equilibrium of the acetic acid is:

CH3COOH ⇄ CH3COO⁻ + H⁺

As the concentration of H⁺ decreases:

A. The equilibrium shifts to the right, to form more products.

In order to restore the initial equilibrium.

Answer:

Empirical formula is C₂H₆S

Explanation:

Given data:

Percentage of hydrogen = 9.73%

Percentage of carbon = 38.66%

Percentage of sulfur = 51.61%

Empirical formula = ?

Solution:

Number of gram atoms of H = 9.73 / 1.01 = 9.6

Number of gram atoms of S = 51.61 / 32 = 1.6

Number of gram atoms of C = 38.66 / 12 = 3.2

Atomic ratio:

             C                      :      H              :         S

           3.2/1.6               :     9.6/1.6       :       1.6/1.6

            2                      :        6             :        1

C : H : S = 2 : 6 : 1

Empirical formula is C₂H₆S.

The enthalpy : 320.3 kJ/mol

The change in enthalpy in the formation of 1 mole of the elements is called enthalpy of formation  

The enthalpy of formation measured in standard conditions (25 ° C, 1 atm) is called the standard enthalpy of formation (ΔHf °)  

Based on the principle of Hess's Law,

the change in enthalpy of a reaction will be the same even though it is through several stages or ways  

Reaction

2Fe (s) + 3Cl₂ (g) → 2FeCl₃ (s) ∆H° = -800.0 kJ/mol  x 2

4Fe (s) + 6Cl₂ (g) → 4FeCl₃ (s) ∆H° = -1600.0 kJ/mol

Si(s) + 2 Cl₂ (g) → SiCl₄ (s) ∆H° = -640.1 kJ/mol

Reverse

SiCl₄ (s) → Si(s) + 2 Cl₂ (g) ∆H° = 640.1 kJ/mol x 3

3SiCl₄ (s) → 3Si(s) + 6Cl₂ (g) ∆H° = 1920.3 kJ/mol

------------------------------------------------------------------------ +

3 SiCl₄ (s) + 4 Fe (s) → 4 FeCl₃ (s) + 3 Si (s) ∆H° = 320.3 kJ/mol

The enthalpy for the formation of 4 moles of [tex]\rm FeCl_3[/tex] has been 320.3 kJ/mol.

The enthalpy of formation of 1 mole at standard temperature and pressure has been termed the standard enthalpy of formation.

The reaction enthalpy to be calculated has reactants of 3 moles of [tex]\rm SiCl_4[/tex], and 4 moles of Fe.

The enthalpy for the formation of [tex]\rm SiCl_4[/tex] has been -640.1 kJ/mol.

The enthalpy for the dissociation of [tex]\rm SiCl_4[/tex] has been the reverse of the formation reaction = +640.1 kJ/mol.

The enthalpy for the dissociation of 3 moles of [tex]\rm SiCl_4[/tex] has been = 3 [tex]\times[/tex] 640.1 kJ/mol.

The enthalpy for the dissociation of 3 moles of [tex]\rm SiCl_4[/tex] has been = 1920.3 kJ/mol.

The enthalpy for the formation of 2 moles of [tex]\rm FeCl_3[/tex] = -800 kJ/mol

The enthalpy for the formation of 4 moles of [tex]\rm FeCl_3[/tex] = -1600 kJ/mol.

The final reaction has 3 moles of  [tex]\rm SiCl_4[/tex], and 4 moles of [tex]\rm FeCl_3[/tex].

Thus, the final enthalpy of reaction will be: 1920 kJ/mol + (-1600 kJ/mol)

The final enthalpy of reaction will be = 320.3 kJ/mol.

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Answer:

okay I will help you just message me johnpatrick on messenger

Answer:

The center of the atom contains the nucleus so yes

Explanation:

Answer:

Its D

Explanation:

I took the quiz

Answer:

D

Explanation:

IT IS REACTING

Answer:

Under balanced its motion under motion its s = d/t under s - d/t is time d = distance s= speed

Explanation:

Answer: Results will tell you which hypothesis is true.

Explanation: The hypothesis becomes a theory if the results support it. d.A new experiment is designed to provide additional data about the hypothesis. Imagine that a team of scientists test a certain hypothesis, and the experimental results show that it is false. ... The results will show which other hypotheses must be true.

Answer:

Manganese (Mn)

Explanation:

We know it's manganese because we are told it is an electrically neutral atom. This means it has the same number of protons and electrons. If it has 25 electrons, it has 25 protons. Protons tell us the atomic number of the atom, which also tells us the name of the element. Manganese is element 25 on the periodic table.

The answer option which is not a necessary input for the process of photosynthesis is: D. [tex]O_2[/tex] (oxygen)

Photosynthesis can be defined as a biological and chemical process through which living organisms such as green plants, transform light energy (sunlight) into chemical energy.

Basically, both sunlight, carbon dioxide ([tex]C0_2[/tex]) and water ([tex]H_2O[/tex]) contained in the Earth's atmosphere plays a significant role in photosynthesis because they serve as an input.

Hence, the necessary input for the process of photosynthesis to take place include the following:

In conclusion, [tex]O_2[/tex] (oxygen) is an end product (output) of photosynthesis rather being an input.

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Answer:

The main function of the immune system is to provide immunity to the body. Immunity is the body's ability to protect itself from the pathogens it is exposed to. Immunity depends on the body's ability to differentiate between things that belong in the body and those that do not. The immune system's first line of defense includes physical and chemical barriers that are always ready and prepared to defend the body from infection.

The skin acts as a barrier against pathogens. Some structures of the first line of defense include the skin, mouth, eyes, ears, nose, and stomach. The skin produces sweat and oil that work together to keep pathogens from the entering the body. Saliva and tears contain substances the can destroy pathogens. The ears and the stomach help fight pathogens.The ears produce ear wax that prevent pathogens from entering the ears. The stomach produces a liquid the kills pathogens.

Mucus is produce by the nose, lungs, throat, and stomach. Mucus traps pathogens. Mucus also prevent pathogens from getting into deep tissues. Anyway, the very first line of defense against any invasion of the human body is a set of physical barriers between the inside of the body and the outer world.

*my notes from edge2020*

Hope this helps ^-^

Answer:

4

Explanation:

[tex]\int\limits^a_b {x} \, dwetjernjtnx[/tex]

Answer:

C₂H₂(g) + 2.5 O₂(g) ⇒ 2 CO₂(g) + H₂O(l)   ΔH° = -1300 kJ/mol

Explanation:

In the combustion of acetylene, it reacts with oxygen to produce carbon dioxide and water. The corresponding chemical equation is:

C₂H₂(g) + 2.5 O₂(g) ⇒ 2 CO₂(g) + H₂O(l)

The thermochemical equation includes the balanced chemical equation, stating the states of aggregation and the enthalpy of the reaction.

C₂H₂(g) + 2.5 O₂(g) ⇒ 2 CO₂(g) + H₂O(l)   ΔH° = -1300 kJ/mol

Answer:

wait

Explanation:

a. The pH of this solution is 9.45.

b. If 0.88 g of NaOH is added to the solution, the pH will be  9.74.

a way to gauge how basic or acidic a material or solution is. On a scale of 0 to 14, pH is measured. A pH of 7 indicates neutrality on this scale, which implies it is neither acidic nor basic. More basic substances have a pH value more than 7, whereas more acidic substances have a pH value less than 7.

first of all we should calculate the molarity of the compounds

no. of moles of NH₃ = weight / molecular weight = 1.68 / (14+3) = 0.099

no. of moles of (NH₄)2SO4 = 4.05 / {2×(14+4) + 32 + 64} = 0.031

no. of moles of NH4+ = 2×0.031 = 0.062

[NH₃] = no. of moles / volume(L) = 0.099/ 0.5 = 0.198

[(NH₄⁺] = 0.031/0.5 = 0.124

1) now we know that

pH + pOH = pkw

pOH = pkw - pH = 14 - pH ---- -1

also

pOH = pkb + log ( [salt]/[base])

from 1

14 - pH = pkb + log ( [salt]/[base])

putting values

14- pH = -log(1.8e-5) + log(0.124/0.198)

14 - pH = 4.54

pH = 9.45

2) if 0.88g NaOH is added then as we know that NaOH is a base then it will reduce the buffer capacity

as there would be OH- ions initially present

hence the buffer action will move backward

i.e

pOH = pkb + log {(salt-x) / (base+x)}

where x= molarity of NaOH

no of moles of NaOH = 0.88 / (23+16+1) = 0.022

molarity of NaOH = 0.022/0.5 = 0.044

then 14 - pH = -log(1.8e-5) + log{ (0.124-0.044) / (0.198+0.044) }

14 - pH = 4.26

pH = 9.74

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