(2) Chapter 2: Measurement Flashcards
(30 cards)
What are the two types of measurements in chemistry?
Qualitative and quantitative
Qualitative measurements describe qualities or characteristics, while quantitative measurements involve numerical values.
Define exact number in the context of measurements and give an example.
A value we can count or that gives a definition
15 pencils or 12= a dozen
What are inexact numbers?
Measured values that include uncertainty
Example: mass of a bean.
Define accuracy in measurement.
How close a measured value is to the actual value.
Define precision in measurement.
How close measured values are to each other.
What are significant figures?
Digits in a measurement that are known with certainty and accuracy.
How many significant figures are in the number 21.623?
5 significant figures
All digits in this number are significant.
How many significant figures are in the number 123?
3 significant figures
All non-zero digits are considered significant.
What is the significance of zeros in significant figures?
Zeros can be significant or non-significant depending on their position
Leading zeros are not significant, while zeros between significant digits and trailing zeros in a decimal context are significant.
Fill in the blank: Any zero between two significant digits and to the right of a decimal point is ______.
significant
This rule helps determine the significance of trailing zeros.
How many significant figures are in the number 1.002?
4 significant figures
The zeros between 1 and 2 are significant.
True or False: Leading zeros in a number are considered significant figures.
False
Leading zeros serve only as placeholders and do not count as significant figures.
What is the rule for determining significant figures when a number ends in a decimal?
Count all digits to the right of the decimal as significant
This rule applies when the number is in decimal form, ensuring that trailing zeros after a decimal point are counted.
How many significant figures are in the number 0.0234?
3 significant figures
Leading zeros are not counted as significant figures.
True or False: The number 160 has three significant figures.
False
The trailing zero in 160 is not considered significant unless specified with a decimal point.
When multiplying 1632 by 2.14, how many significant figures should the final answer have?
3 significant figures
The number 2.14 has 3 significant figures, which determines the precision of the result.
In the multiplication of 12.62 and 3.72 divided by 2.8, how many significant figures should the final result contain?
2 significant figures
In the operation 3.6215 - 4.2, how many digits after the decimal point should the answer have?
The answer should have 1 digit after the decimal point.
What is the result of adding 2.22 x 10^5 and 0.142 x 10^5?
2.36 x 10^5
This is achieved by aligning the exponents and summing the coefficients.
Fill in the blank: Whether positive or negative the highest exponent should always be kept solving equations and the decimal moves to the _______.
left
This is a standard practice in scientific notation to maintain clarity.
How do you express the number 10.124 in scientific notation?
1.0124 x 10^1
This involves moving the decimal one place to the left.
What is the process to add numbers in scientific notation?
Align the exponents and add the coefficients
When adding numbers in scientific notation, ensure that the exponents are the same before performing the addition.
What is the process to multiply numbers in scientific notation?
Multiply the coefficients and add the exponents
For example, (3.24 x 10^n) × (1.3 x 10^m) results in (3.24 × 1.3) × 10^(n+m).
Fill in the blank: When dividing numbers in scientific notation, you should _______.
divide the coefficients and subtract the exponents
