It’s the 3d one
Good luckkkkkkkk
Answer:
only columns
Explanation:
All atoms of elements present in same group or column having same number of valance electrons. Thus the elements in same group having same properties.
For example:
Consider the second group. It consist of alkaline earth metals. There are six elements in second group. Beryllium, magnesium, calcium, strontium, barium and radium.
All have two valance electrons.
Electronic configuration of Beryllium:
Be = [He] 2s²
Electronic configuration of magnesium.
Mg = [Ne] 3s²
Electronic configuration of calcium.
Ca = [Ar] 4s²
Electronic configuration of strontium.
Sr = [Kr] 5s²
Electronic configuration of barium.
Ba = [Xe] 6s²
Electronic configuration of radium.
Ra = [ Rn] 7s²
They are present in group two and have same number of valance electrons (two valance electrons) and show similar reactivity.
They react with oxygen and form oxide.
2Ba + O₂ → 2BaO
2Mg + O₂ → 2MgO
2Ca + O₂ → 2CaO
this oxide form hydroxide when react with water,
BaO + H₂O → Ba(OH)₂
MgO + H₂O → Mg(OH)₂
CaO + H₂O → Ca(OH)₂
With sulfur,
Mg + S → MgS
Ca + S → CaS
Ba + S → BaS
The correct answer is 0.15.
We are aware that there is 0.05 mol of an unidentified hydrocarbon we will refer to as "X" and that its burning produces 6.6 g of carbon dioxide and 3.6 g of water.
These quantities might be converted to moles by applying the following formula:
amount= mass/ relative atomic mass
Thus, the following equation may be written for H2O: moles = 3.6 / 18 = 0.2 and for CO2: moles = 6.6 / 44 = 0.15.
0.05X + x'O2 = 0.15CO2 + 0.2H2O
This may be made simpler by dividing through by 0.05 (this step is likely to be the most helpful to you), resulting in:
1 x + x O2 = 3 co2 + 4 H2O
The hydrocarbon must have been the source of all the carbon in the carbon dioxide and all the hydrogen in the water.
Accordingly, 4 x 2 = 8 moles of H and 3 x 1 = 3 moles of C.
There are 3/1 = 3 Cs and 8/1 = 8 Hs in one X molecule.
This clearly identifies C3H8 or propane as the hydrocarbon X (dividing by 1 seems unnecessary, but it illustrates the process to use if there were more than one mol of X in the first equation).
To learn more about number of moles of carbon dioxide refer the link:
brainly.com/question/12723070
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<span>Buffer systems in our
body maintain the pH of blood to be at an optimum level which is at a range of
7.3-7.4. A buffer is a solution that resists changes in pH during the addition
of an acid or a base. Our blood has a number of buffer systems. Examples are
the bicarbonate buffer system and the hemoglobin buffer system.</span>
If the reaction is
X + Y → Products
Then the rate is
R = k[X]ᵃ [Y]ᵇ
Where,
R = the rate of the reaction (mol L⁻¹ s⁻¹)
k = rate constant
[X] and [Y] = concentrations of the reactants (mol L⁻¹)
a = order of the reaction with respect to X
b = order of the reaction with respect to Y
overall reaction order, n = a + b
according to the given rate expression,
rate = [a][b]³
order of the reaction with respect to 'a' is 1
order of the reaction with respect to 'b' is 3
Overall reaction order = 1 + 3
= 4
