A double replacement reaction occurs when the ionic parts of two ionic compounds are exchanged.
Reaction 1 results in a product which is a single compound. No ionic parts are exchanged.
Reaction 3 results in one compound being separated into its elemental parts. No ionic parts are exchanged.
Reaction 4 has two reactants, but Pb is an element and not an ionic compound. No ionic parts are exchanged.
Hence, the answer is Reaction 2. Both NaBr and Ca(OH)2 are ionic compounds. Br - is the anion in NaBr, and (OH)2 is also an anion. Ionic parts are exchanged.
Answer: a) 8.779 years
b) 8.664 years
<u>Step-by-step explanation:</u>
a)

- A: accumulated amount (balance)
- P: principal amount (original/initial investment)
- r: interest rate (convert to a decimal)
- n: number of times compounded per year
- t: number of years
Given: A = 1800, P = 900, r = 8% = 0.08, n = 3, t = unknown

b)


Answer:
Any of the individual surfaces of a solid object pattern of three dimensional shapes.
Step-by-step explanation:
Surface area of a solid object is the measure of the total area of the surface of three dimensional objects. Example a sphere and a cube is a three dimensional objects.
Answer:
8x + 3
Step-by-step explanation:
In the expression -3x + 14 - 11 + 11x, we have two pairs of like terms that can be combined together:
-3x, 11x
14, -11
If we rewrite this expression with the like terms together, it would look like this:
-3x+11x + 14-11
To make the addition of -3x and 11x easier, we could switch their places in the expression to make it look like this:
11x-3x + 14-11
(Note: Even though we are switching the terms' places, the -3x still keeps its negative sign when you move it around.
11x-3x is 8x and 14-11 is 3.
Therefore, the expression -3x + 14 - 11 + 11x can be simplified by combining like terms into 8x + 3.