You must see the mass of Gallium in the periodic table. The mass present there is calculated by a weighted average of the mass of the isotopes, where the weights are the abundances of each isotope. Let X the isotopic abundance of Ga⁷¹. Since there are only Ga⁶⁹ and Ga⁷¹, the isotopic abundance of Ga⁶⁹ is 1-X. Then:
I don't know the options, but probably 40% is the closest to 36.15%.
Answer:
A. They must be kept separate from moisture and oxygen
Explanation:
Alkali metals refers to a group of chemical elements in the periodic table. It is the common name given to Group 1 elements (excluding hydrogen). They are generally metallic in nature with physical properties like shining lustre, silvery in appearance etc. Alkali metals include lithium, Pottasium, Sodium, Rubidium etc.
One important chemical property of alkali metals is their high reactivity i.e. they tend to react quickly with other substances. For example, alkali metals react vigorously with water to form hydroxides. They also react with oxygen to form oxides. Due to this highly reactive properties, they are kept or stored away from moisture (water) and oxygen (present in air).
Answer:
0.3 s.
Explanation:
Half-life of a first order reaction is defined as the the time taken for any fraction of the reaction to complete is independent of the initial concentration.
Half-life of a first order reaction, t° = 0.693/k
where,
t° = half-life of the reaction
k = rate constant
= 2.3 s^-1
Therefore,
t° = 0.693/2.3
= 0.30 s.
Answer:
There are 5 significant figures
Explanation:
The significant figures are: 2 3 4 7 9
Reducing agent is an compound/atom, that loses an electron and is oxidized.
0.........+I.............+II............0
Ca + 2HCl ----> CaCl₂ + H₂
Calcium is oxidized --- it's reducing agent (reductant).
Hydrogen is reduced --- HCl is oxidizing agent.
