Answer:
1. b
2.a
Explanation:
Photosynthesis is a useful reaction because it provides plants with food.... Rusting has disadvantages
Rusting is a slow process... complete combustion requires a lot of oxygen... photosynthesis requires carbon(IV) oxide and not oxygen
Answer:
1.35 moles of O²⁻
21.6 grams of O²⁻
Explanation:
We know that the charge on Aluminium ion is +3 (i.e. Al³⁺) while, the charge on Oxide ion is -2 (i.e. O²⁻). Therefore, the overall neutral Al₂O₃ compound has 2 Al³⁺ ions and 3 O²⁻ ions. Since, we can say that,
1 mole of Al₂O3 contains = 3 moles of O²⁻ ions
So,
0.450 moles of Al₂O₃ will have = X g of O²⁻
Solving for X,
X = 0.450 mol × 3 mol ÷ 1 mol
X = 1.35 moles of O²⁻
As the mass of an atom is mainly due to the presence of protons and neutrons hence, the addition of two electrons (-ve 2 shows two gained electron) to Oxygen will make a negligible change to the atomic masss of Oxygen because electron is said to be almost 1800 times lighter than proton. Hence, the ionic mass of O²⁻ will be 16 g/mol and the mass of given moles is calculated as,
Mass = Moles × Ionic Mass
Mass = 1.35 mol × 16 g/mol
Mass = 21.6 g
Answer:
Answer to the following question is as follows.
Explanation:
Acid rain causes harm to houses and buildings by dissolving stone or corroding metal exposed to the elements. Acid rain can degrade calcium carbonate or calcium-based chemicals found in some of these products.
The acidic particles damage metal and accelerate the deterioration of paint and stone. They also make buildings and other structures, like as monuments, filthy.
To begin this, you'll first note down the valencies of atoms you're sure about.
K is always 1+
And O is always 2-, except for in peroxide where it is 1-.
So now you must remember that a compound is always neutral. Your net charge has to be 0.
K2Cr2O7.
K2 (1+ x 2) = 2+
Cr (2x) = 2x
O7 (2- ×7) = 14-
+2 +2x + (-14) = 0
•Simple algebra.
2x -12 = 0
2x = 12
x = +6.
Each Cr atom has an oxidation number of +6.
It has to be dilute since the crystal dissolved and unsaturated for the same reason so B
