Answer: <em>The number placed in front of a compound to balance a chemical reaction is called </em><em><u>coefficient</u></em>.
Explanation:
Assume this general form for a <em>chemical equation</em>:
- <em>a</em>A + <em>b</em>B → <em>c</em>C + <em>d</em>D
The letters <em>a, b, c, </em>and <em>d,</em> in front of each compound A, B, C, and D, are called coefficients and indicate the number of formula units (molecules or ions) that take part in the equation.
Those coefficients are needed to <em>balance the equation</em> and ensure compliance with the law of mass conservation.
This example shows it:
- Word equation: hydrogen + oxygen yields water
- Chemical equation: H₂ (g) + O₂(g) → H₂O(g)
- Balance, adding the coefficients so that the number of each kind of atoms is the same on the left and the right of the chemical equation:
H₂ (g) + 2O₂(g) → 2H₂O(g)
In that equation:
- The coefficient of H₂ (g) on the left is 1 (it is not written)
- The coefficient of O₂(g) on the left is 2
- The coefficient of H₂O(g) on the right is 2
You read it as: 1 mole of gaseous hydrogen and 2 moles of gaseous oxygen yield 2 moles of water vapor.
Answer: A. 
Explanation:
The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.
Q = Heat absorbed = 4.56 J
m = mass of substance = 123 g
c = specific heat capacity = ?
Change in temperature ,
Putting in the values, we get:
The specific heat of a 123 g substance that requires 4.56 J of heat in order to increase its temperature by 12.32 °C is
Answer:
2.772 seconds
Explanation:
Given that;
t1/2 = 0.693/k
Where;
t1/2 = half life of the reaction
k= rate constant
Note that decomposition is a first order reaction since the rate of reaction depends on the concentration of one reactant
t1/2 = 0.693/2.5 x 10-1 s-1
t1/2= 2.772 seconds
The name of the ion is Copper.
<u>Explanation</u>:
- Copper is a chemical element symbolized as Cu. It has different ions, one of which is Cu(2+) and Cu(1+).
- Copper on losing 2 electrons forms the ion Cu(2+)
- Copper(2+) is an ion that carries double positive charge.
- It plays the role of a cofactor.
- It is also more stable than the single positive ion Cu(1+)
