Use your calculator to determine the answer to the following calculation: 1.0×10−154.2×10−7
2 answers:
Results of operations count: -1539 or 2.4 .10⁻⁹ (two significant figure)
<h3>Further explanation</h3>Calculating operations in mathematics consist of the operations of addition, subtraction, division, and multiplication.
In one arithmetic operation can have all four operations above, which are called mixed arithmetic operations
We must know the order in which the arithmetic operations must be done first.
The order of the process follows the PEMDAS system, namely: Parentheses, Exponents, Multiplication, Division, Addition, Subtraction.
So:
- 1. If there are parentheses, then do it first
- 2. multiplication and division operations have the same degree, so it is done from the left first
- 3. operations of addition and subtraction calculations also have the same degree so that it can be done from the left first
In the following calculation 1.0 × 10−154.2 × 10−7
1. we prioritize the multiplication operation from the left then after that the subtraction operation, we get:
= 10 - 1542 - 7
= - 1539
2. If it is considered that the problem is a division of rank numbers(scientific notation)
1.0 × 10⁻¹⁵ : 4.2 × 10⁻⁷
then we use principles in rank operations
General properties of numbers:
• 1. aᵇ x aⁿ = aᵇ⁺ⁿ
• 2. aᵇ: aⁿ = aᵇ⁻ⁿ, a ≠ 0
• 3. a⁻ᵇ = 1 / aᵇ, a ≠ 0
• 4. (aᵇ) ⁿ = aᵇⁿ
• 5.
aⁿ: rank number
Then the solution:
We divide the principal numbers first and then the rank numbers, then we multiply the results of the two operations
1. division of principal numbers
1: 4.2 = 0.238
2. division of rank numbers
10⁻¹⁵: 10⁻⁷ = 10⁻⁸
Both of the result we multiply becomes:
0.238 .10⁻⁸, in the form of scientific notation becomes:
2.38 .10⁻⁹ or
2.4 .10⁻⁹ (two significant figure)
<h3>Learn more</h3>rank number
a composite number
Keywords: scientific notation, rank number, significant figure, PEMDAS
You might be interested in
<u>Answer:</u> The limiting reagent in the reaction is bromine.
<u>Explanation:</u>
Limiting reagent is defined as the reagent which is completely consumed in the reaction and limits the formation of the product.
Excess reagent is defined as the reagent which is left behind after the completion of the reaction.
Given values:
Moles of iron = 10.0 moles
Moles of bromine = 12.0 moles
The chemical equation for the reaction of iron and bromine follows:
By the stoichiometry of the reaction:
If 3 moles of bromine reacts with 2 moles of iron
So, 12.0 moles of bromine will react with = of iron
As the given amount of iron is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.
Hence, bromine is considered a limiting reagent because it limits the formation of the product.
Thus, the limiting reagent in the reaction is bromine.
Here you are! I hope it helps, and also for the ones I put a red ‘x’ it depends on how you round it.
