Answer: Mixture
Explanation:
Element is a pure substance which is composed of atoms of similar elements.
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.
Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present. Example: Air which conatins a mixture of 
, 
, 
and 
Answer:
The correct option is C ( the activation energy is lowered, the reactant molecules collide more frequently and with greater energy per collision).
Explanation:
The rate of a chemical reaction is defined as the quantity of products that are formed per unit time. Rates can be computed based on either how the reactants are used up or how products are formed.
There are factors that affects the rate of a chemical reaction and they include TEMPERATURE, catalyst, surface area of reacting substances and many among others.
TEMPERATURE increase in most chemical reactions increases the rate of the reaction. This is because molecules gain more energy at higher temperatures. This increases their kinetic energy resulting in more effective collision of the reactant molecules. The rate of reaction depends on the frequency of this effective collisions between the reacting particles.
Effective collision are those that result in reactions, which when they occur, the colliding particles become activated with increased kinetic energy. This kinetic energy must exceed a particular energy barrier for a particular reaction if the reaction must take place. This energy barrier that must be overcome is known as the ACTIVATION ENERGY.
You need to use the Ka for the acetic acid and the equilibrium equation.
Ka = 1.85 * 10^ -5
Equilibrium reaction: CH3COOH (aq) ---> CH3COO(-) + H(+)
Ka = [CH3COO-][H+] / [CH3COOH]
Molar concentrations at equilibrium
CH3COOH CH3COO- H+
0.50 - x x x
Ka = x*x / (0.50 - x) = x^2 / (0.50 - x)
Given that Ka is << 1 => 0.50 >> x and 0.50 - x ≈ 0.50
=> Ka ≈ x^2 / 0.50
=> x^2 ≈ 0.50 * Ka = 0.50 * 1.85 * 10^ -5 = 0.925 * 10^ - 5 = 9.25 * 10 ^ - 6
=> x = √ [9.25 * 10^ -6] = 3.04 * 10^ -3 ≈ 0.0030
pH = - log [H+] = - log (x) = - log (0.0030) = 2.5
Answer: 2.5
True <span>Nuclear energy is made from the element carbon</span>
Answer:
a. ΔH⁸ = -1420 kJ/mol b. ΔH⁸ = -1144.84 kJ/mol
Explanation:
a.
C₂H₄ (g) + 3 O₂ (g) ------------------------ 4 CO₂ (g) + 2 H₂O (l) ΔH⁸ = ?
ΔH⁸f kJmol 52.47 0 -399.5 -285.83
ΔH⁸ = 2(-399.5) + 2 (-285.83) - (52.47)
ΔH⁸ = -1420 kJ/mol
b.
H₂S (g) + 3 O₂ (g) ---------------------- 2 H₂O (l) + 2 SO₂ (g)
ΔH⁸f kJmol -20.50 0 -285.83 -296.84
ΔH⁸ = 2(-285.83) + 2 (-296.84) - (-20.50)
ΔH⁸ = -1144.84 kJ/mol
