Answer:
+2
Explanation:
Alkaline earth metals are present in group 2 of periodic table. 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 oxidation state +2 by loosing two valance electrons. They also 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
A 2.200-g sample of quinone (C6H4O2) is burned in a bomb calorimeter whose total heat capacity is 7.854<span> kJ/°C. The temperature of the calorimeter increases from 23.44 to </span>30.57 °C<span>. </span>
Shift to reactants(left)
<h3>Further explanation
</h3>
A buffer solution is a solution that can maintain a good pH value due to the addition of a little acid or a little base or dilution.
The buffer solution can be acidic or basic
Acid buffer solutions consist of weak acids and their salts.
A buffer solution of NaC2H202 and HC2H2O2 (acetic acid) is included in the acid buffer
So :
a slight addition of acid (H⁺) will be balanced by the conjugate base
the addition of a small base (OH⁻) will be balanced by the weak acid
With the addition of acid (H +), the equilibrium will shift to the left, in the formation of CH3COOH. The added acid will be neutralized by the conjugate base component (CH3COO−).
Answer:
Gold: 1.1 x 10²² atoms/cm³
Silver: 4.8 x 10²² atoms/cm³
Explanation:
100 g of the alloy will have 29 g of Au and 71 g of Ag.
19.32 g Au ____ 1 cm³
29 g Au ______ x
x = 1.5 cm³
10.49 g Ag ____ 1 cm³
71 g Ag _______ y
y = 6.8 cm³
The total volume of 100g of the alloy is x+y = 8.3 cm³.
Gold:
196.97 g Au____ 6.022 x 10²³ atoms Au
29 g Au _______ w
w = 8.9 x 10²² atoms Au
8.9 x 10²² atoms Au ____ 8.3 cm³
A ____ 1 cm³
A = 1.1 x 10²² atoms Au
Silver:
107.87 g Ag____ 6.022 x 10²³ atoms Ag
71 g Ag _______ w
w = 4.0 x 10²³ atoms Ag
4.0 x 10²³ atoms Ag ____ 8.3 cm³
B ____ 1 cm³
B = 4.8 x 10²² atoms Ag
Answer:
C. Rows 6 and 7, separated from the rest of the table
Explanation:
The lanthanides and actinides are groups of elements in the periodic table, that are thirty (30) in number. They are separated from the rest of the periodic table, usually appearing as separate rows at the bottom. They are often called the inner transition metals, because they all fill the f-block.
Therefore, the correct option is C
" They are found in Rows 6 and 7, separated from the rest of the table"
