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There are various kind of elements that are present in periodic table. Some elements are harmful, some are radioactive, some are noble gases. Option C is correct option.

What is periodic table?

Periodic table is a table in which we find elements with properties like metals, non metals, metalloids and radioactive element arranges in increasing atomic number.

Periodic table help a scientist to know what are the different types of elements are present in periodic table so that they can discover the new elements that are not being discovered yet.

Periodic table is the best platform to have a look to all elements at once that are arranged in columns and groups mentioning their valencies, electronegativity and Ionisation energy symbols. Thus the option c is correct option.

Learn more about periodic table , here:

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Answer:

2.0 x 10^-2 kg/mol

Explanation:

Answer:

just did it the answers b

Explanation:

Answer: [tex]Na_2CO_3+2HCl\rightarrow 2NaCl+H_2O+CO_2[/tex]

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

The balanced chemical equation will be:

[tex]1Na_2CO_3+2HCl\rightarrow 2NaCl+H_2O+1CO_2[/tex]

Thus the numbers that go in the blanks are 1, 2, 2, and 1 respectively for [tex]Na_2CO_3[/tex], [tex]HCl[/tex] , [tex]NaCl[/tex] and [tex]CO_2[/tex] respectively.

Answer:

The correct answer is 0.12 grams.

Explanation:

The mass of carbon monoxide or CO collected in the tube can be determined by using the ideal gas equation, that is, PV = nRT.

Based on the given question, P or the pressure of the gas is given as 1 atm, volume of the gas collected in the tube is 117 ml or 0.117 L.  

The number of moles or n can be determined by using the equation, mass/molar mass.  

R is the universal gas constant, whose value is 0.0821 L atmK^-1mol^-1, and temperature is 55 degree C or 328 K (55+273).  

On putting the values we get:

n = PV/RT

= (1 atm*0.117 L) / (0.0821 L atmK^-1mol^-1 * 328 K)

= 0.0043447 mol

Therefore, mass of CO will be moles * molar mass of CO

= 0.0043447 mol * 28 g/mol

= 0.12 g

Answer:

c

Explanation:

Answer:

0.517

Explanation:

HCN + NaOH → NaCN + H2O [balanced as written]

(35.4 mL) x (0.268 M NaOH) x (1 mol HCN / 1 mol NaOH) / (18.35 mL HCN) = 0.517 M HCN

Answer: 0.517

Explanation:

Answer:

Check the explanation

Explanation:

Sample volume V= 10 mL/min x 17 h x 60 min/h / 1000 mL/L = 10.2 L

The concentration is increased

             10200 mL (sample volum) / 10 mL (eluted sample) = 1020 times.

57x10-9 M / 1020 = 5.6x10-12 M    

1.5 M HNO3 will contain ≤ 2ppm x (1.5M/15.7M ) ≤ 0.190 ppm ≤ 190 ppb

Ignoring this is reagent impurity and calculating for sea water

≤ 190 ppb /1020 = 0.186 ppb = 0.186 x 10-9g/mL = 0.186 x 10-6g/L =

0.186 x 10-6g/L / 56 g/mol = 0.003 x10-6 M = 3 nM

Answer:

46.07 g/mol is the molar mass of ethonal

Answer:

0.10 amps

Explanation:

Answer:

Table salt (the iodine isn't important) consists of much smaller particles than rock salt and therefore has a much higher ratio of surface area to mass. Since chemical reactions occur at surfaces,the smaller table salt particles will dissolve far more quickly than the larger rock salt.

Explanation:

Answer:

Individual salt crystals

Explanation:

A given quantity of solute dissolves faster when it is ground into small particles than if it is in the form of a large chunk because more surface area is exposed.

Give me a good review if right please.

Answer:

1.52M in NaCl

Explanation:

Molarity = moles solute / volume solution in Liters

=> molarity (M) = 3.8 moles / 2.5 Liters solution = 1.52 molar solution in NaCl

Answer: 1.52

Explanation:

Answer:

octet rule

Explanation:

It refers to the tendency of atoms to prefer to have eight electrons in the valence shell.

Answer:

right now we are using energy by online learning on our laptops , air conditioning, and transportation

Explanation:

Answer:

120.4 gradius Celcius

Explanation:

Please see the step-by-step solution in the picture attached below.

Hope this answer can help you. Have a nice day!

Sublevel 2s and 2p contains the valence electrons for nitrogen.

Answer:

6 cm Hg

Explanation:

Boyles Law: P1V1=P2V2

(100 mL)(x)=(20 mL)(30 cm Hg)

x = 6 cm Hg

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Answer:

a)

[H₂O] = 0.0455M

[Cl₂O] = 0.0130M

[HOCl] = 0.0200M

b) Kc = 0.676

c) [H₂O] = [Cl₂O] = 0.177M

Explanation:

Based on the reaction:

H₂O(g) + Cl₂O(g) ⇄ 2HOCl(g)

Kc is defined as:

Kc = [HOCl]² / [H₂O][Cl₂O] For molar concentrations in equilibrium

As volume of the flask is 1.00L, the initial molar concentrations of H₂O and Cl₂O is 0.0555M and 0.0230M, respectively.

In equilibrium, the concentrations are:

[H₂O] = 0.0555M - X

[Cl₂O] = 0.0230M - X

[HOCl] = 2x = 0.0200M → X = 0.0100M

Where X is reaction coordinate

a) Concentrations in equilibrium are:

[H₂O] = 0.0455M

[Cl₂O] = 0.0130M

[HOCl] = 0.0200M

b) Replacing in Kc:

Kc = [0.0200]² / [0.0455][0.0130] = 0.676

c) Initial concentration of HOCl is 1.0mol / 2.0L = 0.50M. In equilibrium concentrations are:

[H₂O] = X

[Cl₂O] = X

[HOCl] = 0.50M - 2X

Replacing in Kc formula:

0.676 = [0.50-2X]² / [X][X]

0.676X² = 4X² - 2X + 0.25

0 = 3.324X² - 2X + 0.25

Solving for X:

X = 0.177M

X = 0.425M → False answer, produce negative concentrations.

As X = [H₂O] = [Cl₂O]; equilibrium concentrations of both compounds is 0.177M

Answer:

C

Explanation:

Answer:

I think its q

Explanation:

h is the Planck constant, c the speed of light

Answer:

i don't understand

Explanation:

Answer:

c

Explanation:

Answer:

2

Explanation:

pH+pOH=14

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Answer:

2

Explanation:

Ph+PoH=14

Answer:

A. Buffer strips

Explanation:

The practice that could help reduce erosion of water banks is buffer strips.

Erosion is the action of surface processes that removes soil, rock or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited.

One of the practices that could be used to reduce the effect of erosion is buffer strips.

What buffer strips do is slow and filter storm runoff while helping to hold soil in place.

Learn more on buffer strips here; https://brainly.com/question/26872640

Answer:

gas

Explanation:

If you put gas in anything, it will occupy shape and volume.

Liquid only occupies shape of the container, whereas, solid doesn't occupy shape or volume because it maintains a fixed volume and shape.

Answer:

[tex]pOH=1.3[/tex]

Explanation:

Hello,

In this case, since pH is computed by knowing the concentration of hydrogen ions, one could compute the pOH by knowing the concentration of the hydroxyl ions as in this case which is 0.045M as shown below:

[tex]pOH=-log([OH^-])=-log([0.045])\\\\pOH=1.3[/tex]

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Answer:

The pOH of the 0.045 M solution is 1.3

The second option (1.3) is correct

Explanation:

Step 1: Data given

Concentration [OH-] of KOH is 0.045 M

Step 2: Calculate pOH

pOH = -log[OH-]

pOH = -log (0.045)

pOH = 1.3

The answer:

The pOH of the 0.045 M solution is 1.3

The second option (1.3) is correct

Answer: The volume of solution is 0.0459 L

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution

[tex]Molarity=\frac{n}{V_s}[/tex]

where,

n = moles of solute

[tex]V_s[/tex] = volume of solution in L

moles of HCl (solute) = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{2.43g}{36.5g/mol}=0.0666[/tex]

Now put all the given values in the formula of molality, we get

[tex]1.45M=\frac{0.0666}{V_s}[/tex]

[tex]V_s=\frac{0.0666}{1.45}=0.0459[/tex]

Therefore, the volume of solution is 0.0459 L

Answer:

1.02 g OF CALIFORNIUM-254 WILL REMAIN AFTER 363 DAYS IF 64 g REACTS WITH HALF LIFE OF 60.5 DAYS.

Explanation:

Half life of a chemical reaction is the time required for a radioactive element to decay to half its original mass.

We will use the formula:

                                    Nt = No (1/2)^t/t1/2                                            where;

Nt = quantity of substance remaining = unknown

No = original mass of the substance = 64 g

t = time elapsed = 363 days

t1/2 = half life of the substance = 60.5 days

Putting the values into the equation, we have:

Nt = 64 * (1/2)^(363/60.5)

Nt = 64 * (1/2) ^6

Nt = 64 * 0.015625

Nt = 1.0156

The amount of californium-254 remaining after 363 days is approximately 1.02 g