The molar mass is the mass of a given chemical element or chemical compound (g) divided by the amount of substance (mol). The molar mass of a compound can be calculated by adding the standard atomic masses (in g/mol) of the constituent atoms.

6 0

3 years ago

An atom has a mass number of 52. if there are 27 neutrons in the atom, then the atom must be:

faltersainse [42]

Mass number- number of neutrons= number of protons.
52-27=25 protons.
Number of protons = atomic number =25
It is Mn (manganese).

4 0

3 years ago

For a first-order reaction, after 2.00 min, 20% of the reactants remain. Calculate the rate constant for the reaction. 1. 74.6 s

garri49 [273]

Answer: The rate constant for the reaction is $0.013412s^{-1}$

Explanation:

Rate law expression for first order kinetics is given by the equation:

$k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}$

where,

k = rate constant = ?

t = time taken for decay process = 2.00 min = 120 seconds (Conversion factor: 1 min = 60 seconds)

$[A_o]$ = initial amount of the sample = 100 grams

[A] = amount left after decay process = 20 grams

Putting values in above equation, we get:

$k=\frac{2.303}{120}\log\frac{100}{20}\\\\k=0.013412s^{-1}$

Hence, the rate constant for the reaction is $0.013412s^{-1}$

7 0

2 years ago