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Mendeleev put elements in groups while creating the periodic table. What important role do groups play in the structure of the p

NikAS [45]

Answer:

Groups show similar chemical properties about the elements

Explanation:

The periodic table is divided into groups and periods. Groups are vertical while periods are horizontal.

All elements in the same group possess the same number of outermost shell electrons. This number of outermost shell electrons controls the reactivity of the elements in the group.

Hence, groups show similar chemical properties of the elements in them, Groups separate elements into families which assist in the speedy study of elements.

3 0

2 years ago

Four animals were fleeing from a wildfire. All of them were running at a speed of 30 miles per hour. Which one has the greatest

RUDIKE [14]

Answer: I don’t know lol

Explanation: I am so sorry I thought this was easy

6 0

2 years ago

Read 2 more answers

What amount (moles) is represented by each of these samples?

Zinaida [17]

<h3>Answer:</h3>

a) Moles of Caffeine = 1.0 × 10⁻⁴ mol

b) Moles of Ethanol = 4.5 × 10⁻³ mol

<h3>Solution:</h3>

Data Given:

Mass of Caffeine = 20 mg = 0.02 g

M.Mass of Caffeine = 194.19 g.mol⁻¹

Molecules of Ethanol = 2.72 × 10²¹

Calculate Moles of Caffeine as,

Moles = Mass ÷ M.Mass

Putting values,

Moles = 0.02 g ÷ 194.19 g.mol⁻¹

Moles = 1.0 × 10⁻⁴ mol

Calculate Moles of Ethanol as,

As we know one mole of any substance contains 6.022 × 10²³ particles (atoms, ions, molecules or formula units). This number is also called as Avogadro's Number.

The relation between Moles, Number of Particles and Avogadro's Number is given as,

Number of Moles = Number of Molecules ÷ 6.022 × 10²³

Putting values,

Number of Moles = 2.72 × 10²¹ Molecules ÷ 6.022 × 10²³

Number of Moles = 4.5 × 10⁻³ Moles

5 0

2 years ago

Consider an amphoteric hydroxide, m(oh)2(s), where m is a generic metal. estimate the solubility of m(oh)2 in a solution buffere

Colt1911 [192]

Missing data in your question: (please check the attached photo)
from this balanced equation:
M(OH)2(s) ↔ M2+(aq) + 2OH-(aq) and when we have Ksp = 2x10^-16
∴Ksp = [M2+][OH]^2
2x10^-16 = [M2+][OH]^2
a) SO at PH = 7
∴POH = 14-PH = 14- 7 = 7
when POH = -㏒[OH]
7= -㏒[OH]
∴[OH] = 1x10^-7 m by substitution with this value in the Ksp formula,
∴[M2+] =Ksp /[OH]^2
= (2x10^-16)/(1x10^-7)^2
= 0.02 M
b) at PH =10
when POH = 14- PH = 14-10 = 4
when POH = -㏒[OH-]
    4 = -㏒[OH-]
∴[OH] = 1x10^-4 ,by substitution with this value in the Ksp formula
[M2+] = Ksp/ [OH]^2
= 2x10^-16 / (1x10^-4)^2
  = 2x10^-8 M
c) at PH= 14
when POH = 14-PH
= 14 - 14
= 0
when POH = -㏒[OH]
  0 = - ㏒[OH]
∴[OH] = 1 m
by substitution with this value in Ksp formula :
[M2+] = Ksp / [OH]^2
= (2x10^-16) / 1^2
= 2x10^-16 M

8 0

2 years ago

Which statement correctly describes an atom of the element helium? (9)

Luden [163]

C. An atom of helium has its valence electrons in its first energy level, it wouldn't and can't satisfy the Octet rule as it only has 2 electrons, but with 2, it has a full shell, as the first energy level can hold only 2 electrons.

8 0

2 years ago