Answer:
Transition metals and lanthanide metals
Explanation:
Alkali metals, alkaline earth metals, halogens, and noble gases are all part of the main group elements.
Periods and families simply refer to the rows and columns of the periodic table. They don't specify the type of element.
Question #1
Potasium hydroxide (known)
volume used is 25 ml
Molarity (concentration) = 0.150 M
Moles of KOH used
0.150 × 25/1000 = 0.00375 moles
Sulfuric acid (H2SO4)
volume used = 15.0 ml
unknown concentration
The equation for the reaction is
2KOH (aq)+ H2SO4(aq) = K2SO4(aq) + 2H2O(l)
Thus, the Mole ratio of KOH to H2SO4 is 2:1
Therefore, moles of H2SO4 used will be;
0.00375 × 1/2 = 0.001875 moles
Acid (sulfuric acid) concentration
0.001875 moles × 1000/15
= 0.125 M
Question #2
Hydrogen bromide (acid)
Volume used = 30 ml
Concentration is 0.250 M
Moles of HBr used;
0.25 × 30/1000
= 0.0075 moles
Sodium Hydroxide (base)
Volume used 20 ml
Concentration (unknown)
The equation for the reaction is
NaOH + HBr = NaBr + H2O
The mole ratio of NaOH : HBr is 1 : 1
Therefore, moles of NaOH used;
= 0.0075 moles
NaOH concentration will be
= 0.0075 moles × 1000/20
= 0.375 M
Answer:
Boron atoms lie in hexagonal aromatic graphite-like layers, with a charge of −1 on each boron atom. Magnesium (II) ions lie between layers Binary metal-boron compounds, the metal borides, contain boron in negative oxidation states. Illustrative is magnesium diboride (MgB 2).
Explanation:
Answer:
70%of 2000 = 1400
2000 tonnes of hematite contains 1400 tonnes iron oxide .
1400 tonnes of fe2O3
fe2O3 have molar mass 159.69
calculate moles = given mass/molar mass
moles = 1400000000/159.69
moles = 8766986
one mole contains = 112 g of fe
so 8766986 moles will contain = 112×8766986
= 981,902,432 grams of ferrous
which is nothing but equal to 981.90 tonnes of iron!!
