Answer: A. It is made of polar molecules.
Explanation:
A polar molecule refers to a molecule that has a covalent bond but has an uneven distribution of electrons due to an atom in the molecule having strong electronegativity which will attract more of the electrons from the other atom.
Water is such a molecule because Oxygen has strong electronegativity which leads to electrons being pulled to it.
Answer:
a) Measurements have a good precision.
Explanation:
Accuracy is the proximity of the data to the value considered as real, in this situation we do not know the real value and we do not know if the data is accurate or not, so we can discard options b and d.
Now, precision is the proximity of the data obtained among themselves and that is what we can observe, so the appropriate answer is the option a.
2NaCN(s) + H₂SO₄(aq) --> Na₂SO₄(aq) + 2HCN(g)
The molar ratio between NaCN : HCN is 2:2 or 1:1
Mass of HCN = 16.7 g
Molar mass of HCN = 1 + 12 + 14 = 27 g/mol
Molar mass of NaCN = 49 g/mol
Therefore, the mass of NaCN is
16.7 g of HCN x 49 g/mol of NaCN / 27 g/mol of HCN = 30.3 grams of NaCN
Therefore, 30.3 grams of NaCN gives the lethal dose in the room.
Answer:
3 moles of Oxygen
Explanation:
The chemical formula of a compound is a representation which shows all the elements therein and the mole relationship between them expressed as subscripts.
NaHCO₃ implies:
1 mole of baking soda contains:
1 mole of Na
1 mole of Hydrogen
1 mole of carbon
And 3 moles of Oxygen
From the equation;
4 Al + 3 O2 = 2 Al2O3
The mole ratio of Oxygen is to Aluminium hydroxide is 3:2.
Therefore; moles of Al2O3 is
(0.5/3 )× 2 = 0.333 moles
Therefore; The moles of aluminium oxide will be 0.333 moles
