Answer: Option (a) is the correct answer.
Explanation:
Atomic number is the sum of only total number of protons present in an element. Whereas mass number is the sum of total number of both protons and neutrons present in an element.
For example, given atom has mass number as 15 and its atomic number is 7.
Therefore, number of neutrons present in it will be calculated as follows.
Mass number = no. of protons + no. of neutrons
15 = 7 + no. of neutrons
no. of neutrons = 15 - 7
= 8
Thus, we can conclude that the given atom contains 8 neutrons in the nucleus.
Answer:
Moles of silver iodide produced = 1.4 mol
Explanation:
Given data:
Mass of calcium iodide = 205 g
Moles of silver iodide produced = ?
Solution:
Chemical equation:
CaI₂ + 2AgNO₃ → 2AgI + Ca(NO₃)₂
Number of moles calcium iodide:
Number of moles = mass/ molar mass
Number of moles = 205 g/ 293.887 g/mol
Number of moles = 0.7 mol
Now we will compare the moles of calcium iodide with silver iodide.
CaI₂ : AgI
1 : 2
0.7 : 2×0.7 = 1.4
Thus 1.4 moles of silver iodide will be formed from 205 g of calcium iodide.
Answer:
d. why matter exists
Explanation:
The kind of questions that chemistry CANNOT answer is "why matter exists".
In Chemistry, question of how the properties, composition and structure of substances are is answered. Also, the transformations that these substances undergo, and the energy that they release or absorbe during the transformation processes are revealed in chemistry.
Chemistry can answer the question of what forms of matter exists but cannot answer why matter actually exists.
Answer:
accretion
Explanation:
the coming together and cohesion of matter under the influence of gravitation to form larger bodies.
