Answer:
(a) 0.8 s
(b) t = 7.2 s
Explanation:
(a) Half life expression for second order kinetic is:
![t_{1/2}=\frac{1}{k[A_o]}](https://tex.z-dn.net/?f=t_%7B1%2F2%7D%3D%5Cfrac%7B1%7D%7Bk%5BA_o%5D%7D)
Where,
is the initial concentration = 1.0 M
k is the rate constant = 1.25 M⁻¹s⁻¹
So,

Half life = 0.8 s
(b) Integrated rate law for second order kinetic is:
![\frac{1}{[A_t]} = \frac{1}{[A]_0}+kt](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B%5BA_t%5D%7D%20%3D%20%5Cfrac%7B1%7D%7B%5BA%5D_0%7D%2Bkt)
Where,
is the final initial concentration
For 90% completion, 10% is left. so,
![[A_t]=\frac {10}{100}\times 1.0=0.1\ M](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5Cfrac%20%7B10%7D%7B100%7D%5Ctimes%201.0%3D0.1%5C%20M)
So,

t = 7.2 s
The molar mass of methylammonium bromide is 111u.
<h3>What is molar mass?</h3>
The molar mass is defined as the mass per unit amount of substance of a given chemical entity.
Multiply the atomic weight (from the periodic table) of each element by the number of atoms of that element present in the compound.
Add it all together and put units of grams/mole after the number.
Atomic weight of H is 1u
Atomic weight of N is 14u
Atomic weight of C is 12u
Atomic weight of Br is 79u
Calculating molar mass of
=2(1 x3+ 14+12+ 1 x 3 +79) = 111u
Hence, the molar mass of methylammonium bromide is 111u.
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The identity of the metal is copper.
<h3>What is specific heat?</h3>
The amount of energy needed to raise the temperature of one gram of a substance by one degree Celsius.
Using the formula of specific heat
H = mcdT
Where, H = Heat absorbed
m = mass of the metal
c = specific heat capacity of the metal
dT = temperature change
Putting the values in the equation
20 J = 0.0052 Kg × c × ( 40.0°C - 30.0°C)
c = 20 J/0.0052 Kg × ( 40.0°C - 30.0°C)
c = 385 JKg-1°C-1
Thus, the metal is copper.
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Answer:
1. Two people stand on the same side of a large tire. Both people pull the tire with equal force.
2. an object’s ability to not change its motion
3. The car moves forward, while inertia keeps the balloon in place.
4. The unbalanced forces of air resistance and gravity slow the airplane and pull it down.
5. The force acting on the object must be unbalanced.
An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. Ionic bonds are formed between a cation, which is usually a metal, and an anion, which is usually a nonmetal. A covalent bond involves a pair of electrons being shared between atoms.