Concentrations of substances dissolved in solution are often expressed as mass per unit volume. For example, normal human blood has a cholesterol concentration of about 200 mg/100 mL. Express this concentration in the following units. (a) mg/L
Ch.1 - Chemical Tools: Experimentation & Measurement
Chapter 1, Problem 103
Among many alternative units that might be considered as a measure of time is the shake rather than the second. Based on the expression 'faster than a shake of a lamb's tail,' we'll define 1 shake as equal to 2.5 * 10-4 s. If a car is traveling at 55 mi/h, what is its speed in cm/shake

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Convert the speed from miles per hour to miles per second by dividing 55 mi/h by 3600 s/h.
Convert the speed from miles per second to centimeters per second by using the conversion factor 1 mile = 160934 cm.
Now, convert the speed from centimeters per second to centimeters per shake by using the conversion factor 1 shake = 2.5 \times 10^{-4} s.
Set up the conversion as a series of multiplication steps, ensuring that units cancel appropriately to leave you with cm/shake.
Perform the calculations step by step to find the final speed in cm/shake.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Unit Conversion
Unit conversion is the process of converting a quantity expressed in one set of units to another set of units. In this question, we need to convert the speed of the car from miles per hour (mi/h) to centimeters per shake (cm/shake). This involves using conversion factors to change both the distance and time units appropriately.
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Conversion Factors
Speed Calculation
Speed is defined as the distance traveled per unit of time. To find the speed in different units, we must first calculate the distance the car travels in a given time frame and then express that distance in the desired units. In this case, we will calculate how far the car travels in one shake and then convert that distance to centimeters.
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Understanding Time Units
Understanding time units is crucial for accurate calculations in physics and chemistry. A shake is defined as 2.5 x 10^-4 seconds, which is significantly shorter than a second. Recognizing this allows us to appropriately relate the speed of the car to the new time unit, ensuring that our final answer is in cm/shake.
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Related Practice
Textbook Question
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Textbook Question
Concentrations of substances dissolved in solution are often expressed as mass per unit volume. For example, normal human blood has a cholesterol concentration of about 200 mg/100 mL. Express this concentration in the following units. (e) How much total blood cholesterol in grams does a per-son have if the normal blood volume in the body is 5 L?
Textbook Question
Administration of digitalis, a drug used to control atrial fibrilla-tion in heart patients, must be carefully controlled because even a modest overdose can be fatal. To take differences between patients into account, drug dosages are prescribed in terms of mg/kg body weight. Thus, a child and an adult differ greatly in weight, but both receive the same dosage per kilogram of body weight. At a dosage of 20 mg/kg body weight, how many mil-ligrams of digitalis should a 160 lb patient receive?
Textbook Question
Which is larger in each pair, and by approximately how much? (a) A liter or a quart
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Textbook Question
Which is larger in each pair, and by approximately how much? (b) A mile or a kilometer
Textbook Question
Which is larger in each pair, and by approximately how much? (c) A gram or an ounce
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