Carry out the following unit conversions: (a) 0.625 atm to torr, (b) 825 torr to atm, (c) 62 mm

Carry out the following unit conversions: (a) 0.625 atm to...

Key Concepts

Dimensional Analysis

Dimensional analysis is a method used to check the consistency of units within calculations and to ensure that an equation or conversion makes sense dimensionally. In unit conversions, it involves tracking and canceling units throughout a calculation, thus providing a logical framework for converting between different measurement systems.

Pressure Units

Pressure units such as atmospheres (atm), torr, millimeters of mercury (mm Hg), kilopascals (kPa), and bars are different ways of expressing pressure. Understanding the relationships among these units, like 1 atm being equivalent to 760 torr or mm Hg, is crucial in fields like physics, chemistry, and engineering, where precise pressure measurements are required.

Conversion Factors

Conversion factors are ratios that express how many of one unit are equal to another unit. These ratios are essential in unit conversion as they provide a way to systematically cancel out unwanted units and introduce the desired units into an expression, ensuring that the final result is presented correctly.

Unit Conversion

Unit conversion is the process of converting a quantity expressed in one set of units to another set of units using conversion factors. This concept is widely applicable in science and engineering, ensuring that measurements can be compared, combined, or used in formulas regardless of the units in which they were initially expressed.

Transcript

00:01 Hello, in problem number 36, we are asked to do some pressure conversions.

00:08 So we have four separate problems here, so let's get started.

00:11 For letter a, we have 0 .625 atmospheres, and we are asked to convert that to tor.

00:21 So we need a conversion factor between atmospheres and tor.

00:26 When i'm doing pressure conversions, i typically just like to use the values for standard pressure.

00:33 For example, i know that standard pressure in atmospheres is one atmosphere, and standard pressure in tor is 760.

00:43 So if both of these equal standard pressure, i know they are equal, and i can use them as a conversion factor.

00:50 So there are 760 tor are equal to one atmosphere.

00:55 This allows me to cancel atmosphere, and by multiplying, i get the answer, 475 tor.

01:11 So part b, we're starting with 825 tor and are asked to reverse the process and convert this to atmospheres.

01:23 So that means i need to reverse my conversion factor.

01:28 I will have one atmosphere in the numerator and 760 tor in the denominator.

01:37 Calculating this and rounding it to three significant figures since 825 had three.

01:42 I get 1 .09 atmospheres.

01:52 For part c, we are starting with millimeters of mercury.

01:57 We have 62 millimeters of mercury.

02:01 And we're trying to convert to tor.

02:06 As i said, i like to use the values for standard pressure because that way i don't have to remember anything else.

02:14 I know that 760 tor is standard pressure, and i know that 760 millimeters of mercury is also standard pressure.

02:23 Pressure...

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