1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Marina CMI [18]
3 years ago
5

What element is located in group 2, period 2?

Chemistry
1 answer:
telo118 [61]3 years ago
7 0

This element is beryllium.

If you find my answer helpful, please brainliest me!

You might be interested in
Be sure to answer all parts. What is the [H3O+] and the pH of a buffer that consists of 0.26 M HNO2 and 0.89 M KNO2? (K, of HNO2
Aleksandr-060686 [28]

Answer : The H_3O^+ ion concentration is, 1.12\times 10^{-3}M and the pH of a buffer is, 2.95

Explanation : Given,

K_a=7.1\times 10^{-4}

Concentration of HNO_2 (weak acid)= 0.26 M

Concentration of KNO_2 (conjugate base or salt)= 0.89 M

First we have to calculate the value of pK_a.

The expression used for the calculation of pK_a is,

pK_a=-\log (K_a)

Now put the value of K_a in this expression, we get:

pK_a=-\log (7.1\times 10^{-4})

pK_a=4-\log (7.1)

pK_a=3.15

Now we have to calculate the pH of the solution.

Using Henderson Hesselbach equation :

pH=pK_a+\log \frac{[Salt]}{[Acid]}

pH=pK_a+\log \frac{[KNO_2]}{[HNO_2]}

Now put all the given values in this expression, we get:

pH=3.15+\log (\frac{0.89}{0.26})

pH=2.95

The pH of a buffer is, 2.95

Now we have to calculate the H_3O^+ ion concentration.

pH=-\log [H_3O^+]

2.95=-\log [H_3O^+]

[H_3O^+]=1.12\times 10^{-3}M

The H_3O^+ ion concentration is, 1.12\times 10^{-3}M

4 0
3 years ago
Which of the following processes would you predict to have an increase in entropy?
Anna [14]
C. Melting ice. 
It is C because melting ice is a change of state from solid to liquid which requires an addition of energy(or entropy) into the system.
Condensation of water occurs from a gas to a liquid state, which takes energy out of the system(water) and gives it to the surroundings(air around it). Freezing water is the same as condensation except for the state change. Deposition is simply gas to a solid instantaneously so you can again see it as with the other two examples. 

6 0
3 years ago
Classify the following as either solutions or colloids. If a colloid, name the type of colloid and identify both the dispersed a
aev [14]

Answer:

a. glucose in water( solution)

b. smoke in air (colloids)

c. carbon dioxide in air (solution)

d. milk( colloids)

Explanation:

A solution is said to be formed when a solute dissolves in a solvent to form a homogeneous mixture. The solute particles are less than 10^-9m in size. Familiar solutions are those where the solute are dissolved in a liquid solvent. When the liquid water, the solution is known as an aqueous solution. A typical example is (glucose in water). In some other cases, the apparent solution of a solute in a solvent is accompanied by a chemical reaction and this is often known as a chemical reaction. A typical example is (carbon dioxide in air).

Colloids are also known as false solutions. Here, the individual solute particles are larger than the particles of the true solution, but not large enough to be seen by the naked eye. When a light beam is placed beside a beaker containing a colloid, the light rays of the beam can be clearly seen. This shows that it exhibits the Tyndall effect while a solution dosent exhibit such.

In a colloid, the liquid solvent is more appropriately know as the DISPERSION medium while the solid solute particles constitute the DISPERSED substance. This can either be solid, liquid or gas.

For example:

--> smoke in air : Dispersion medium is gas while the dispersed substance is solid.

--> milk: Dispersion medium is liquid while the dispersed substance is liquid.

7 0
3 years ago
4. "Metals are conductor of electricity"prove​
Nikolay [14]

Answer:

Hey mate.......

Explanation:

This is ur answer......

<em>Metals are an excellent conductor of electricity and heat because the atoms in the metals form a matrix through which outer electrons can move freely. Instead of orbiting their respective atoms, they form a sea of electrons that surround the positive nuclei of the interacting metal ions.</em>

Hope it helps!

mark me brainliest pls......

Follow me! :)

8 0
3 years ago
The half-life of cesium-137 is 30 years. suppose we have a 200-mg sample.
Assoli18 [71]
a) To find  the mass after t years:

we will use this formula:

A = Ao / 2^n 

when A =the amount remaining

and Ao = the initial amount

and n = t / t(1/2)

by substitution:

∴ A = 200 mg/ 2^(t/30y)


b) Mass after 90 y :

by  using the previous formula and substitute t by 90 y

A = 200mg/ 2^(90y/30y)

∴ A = 25 mg

C) Time for 1 mg remaining:

when A= Ao/ 2^(t/t(1/2)

so, by substitution:

1 mg = 200 mg / 2^(t/30y)

∴2^(t/30y) = 200 mg  by solving for t

∴ t = 229 y 


7 0
3 years ago
Other questions:
  • 1.88gof potassium chloride is dissolved in300.mLof a23.0mMaqueous solution of silver nitrate.Calculate the final molarity of chl
    7·1 answer
  • HELLPPPPPPPPPPPPP<br> :((((((((
    13·2 answers
  • 1. If you run into a curb on a skateboard, you will fall forward off your skateboard because
    5·2 answers
  • What does a soloniod not have
    8·1 answer
  • How does the kinetic-molecular theory explain the following properties of liquids:
    10·1 answer
  • describe how 250 cm³ of 0.2 mol/dm³ H2SO4 could be prepared from 150 cm³ of 1.0mol/dm³ stock solution of the acid​
    10·1 answer
  • In the tropical rainforests, birds have evolved to eat the brightly-colored fruits. The fruits have evolved their attractive col
    11·1 answer
  • During photosynthesis, carbon dioxide and water react to produce glucose and oxygen. Which statement explains why photosynthesis
    13·1 answer
  • 2. What is the temperature (°C) of 1.50 moles of gas stored in a 10.0 L container at 1558 mm
    9·1 answer
  • True or false: For a spontaneous redox reaction, the products are stronger oxidizing and reducing agents than the reactants.
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!