By using the ICE table :
initial 0.2 M 0 0
change -X + X +X
Equ (0.2 -X) X X
when Ka = (X) (X) / (0.2-X)
so by substitution:
4.9x10^-10 = X^2 / (0.2-X) by solving this equation for X
∴X ≈ 10^-6
∴[HCN] = 10^-6
and PH = -㏒[H+]
= -㏒ 10^-6
= 6
Answer:
true because of the elements
Answer:
Explanation:
Two moles of magnesium (Mg) and five moles of oxygen (O2) are placed in a reaction vessel. When magnesium is ignited, it reacts with oxygen. What is the limiting reactant in this experiment?
Mg + O2 → MgO (unbalanced)
first, balance the equation
2Mg +O2-------> 2MgO
two magnesium atoms react with one diatomic oxygen molecule
there is a 1:1 ratio of magnesium to oxygen atoms
but we have 2 moles of magnesium atoms and 2X5 = 10 moles of oxygen atoms
the lesser magnesium LIMITS the amount of product we can make, so it is the LIMITING REAGENT.
Answer:
The false statement is :
- Pyrite is an ore of gold and is used in jewelry making.
- Cobalt is not used in medicine.
Explanation:
Pyrite is an ore of iron sulfide found on the Earth and in coal, limestone and in many deposits of metallic ores. Due to its luster and pale yellowish color it appears as gold due to which it is also termed as Fool's gold.
It is used in firearms , in production of sulfur dioxide gas, etc.
Cobalt is used as medicine to treat cancer patient. Co-60 is used in treatment of cancer in which gamma rays produced by Co-60 are used to kill tumor cells in a cancer patient.
Where as talc is used in industries like : paper making, food, paints, plastics etc. Quartz is primary material used to prepare glass and cobalt is used as
The maximum number of covalent bonds formed by a single carbon atom is 4