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Express a mass of 76g in the unit of kilogram 76g x 1kg = 0.076kg
Mass and Volume Mass: measures the amount of matter in an object Express a mass of 76g in the unit of kilogram 76g x 1kg = kg 1000g
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Measuring Liquid Volume
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Volume – SI derived unit for volume is cubic meter (m3)
1 cm3 = (1 x 10-2 m)3 = 1 x 10-6 m3 1 dm3 = (1 x 10-1 m)3 = 1 x 10-3 m3 1 L = 1000 mL = 1000 cm3 = 1 dm3 1 mL = 1 cm3 1.7 Measuring Liquid Volume Express the volume of 364 mL in liters
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Density – SI derived unit for density is kg/m3
1 g/cm3 = 1 g/mL = 1000 kg/m3 d = m V density = mass volume
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A piece of platinum metal with a density of 21
A piece of platinum metal with a density of 21.5 g/cm3 has a volume of 4.49 cm3. What is its mass? d = m V m = d x V = 21.5 g/cm3 x 4.49 cm3 = 96.5 g 1.7
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K = 0C 0F = x 0C + 32 9 5 1.7 273 K = 0 0C 373 K = 100 0C 32 0F = 0 0C 212 0F = 100 0C 0C = x (0F – 32) Kelvin is the SI Unit of temperature: absolute temperature scale. 0K is the lowest temperature that can be achieved theoretically.
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Convert 172.9 0F to degrees Celsius and Kelvin.
0F = x 0C + 32 9 5 0F – 32 = x 0C x (0F – 32) = 0C 0C = x (0F – 32) 0C = x (172.9 – 32) = 78.3 1.7
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Heat and Calorimetry Heat is the transfer of thermal energy between two bodies that are at different temperatures. Temperature is a measure of the thermal energy. Temperature = Thermal Energy
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Energy Units • joule = J = 1 kg-m2/s2 • calorie = J • 1 L-atm = J • Food calorie = Cal = 1000 cal
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Calorimetry- the measurement of heat.
The specific heat (Cp) of a substance is the amount of heat (q) required to raise the temperature of one gram of the substance by one degree Celsius. The higher a substance’s specific heat, the more slowly its temperature rises in response to heating. The heat capacity of a substance is the amount of heat (q) required to raise the temperature of a given quantity (m) of the substance by one degree Celsius. Heat (q) absorbed or released: q = m x Cp x Dt Dt = tfinal - tinitial
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Heat is often measured by the rise in the temperature of a given mass of water in a device called a calorimeter. The heat capacity of water is J / (g oC) so the relationship between heat added, mass of water, and temperature change becomes: Heat = (4.184 J/g oC) x mass of water (g) x T (oC)
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The basal metabolic rate (BMR), of a human at rest with an empty gastrointestinal tract is measured by a more complex calorimeter. This device involves a room in which the patient reclines. The walls of the room are surrounded by a hollow jacket through which water flows at a fixed rate. The temperature of the water leaving the room will be higher than that entering the room due to the heat being given off by the patient. By knowing the heat capacity of water (4.184 J / g oC), the amount of water that has flowed about the room, and the difference in temperature between the inflowing and outflowing water, the heat given off by the patient in a given time may be measured.
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Because the calorimeter for determining a BMR is so elaborate, an alternate way of obtaining a BMR is available. It has been determined that an adult human male produces about 4.8 kcal of heat per liter of oxygen gas consumed. Oxygen uptake at rest can therefore be directly related to a patient’s BMR.
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The Composition of Matter
Chapter 1 Summary The Composition of Matter • Substances are classified on the basis of their composition. • The purity of a substance is established by verifying that one and only one substance is present. • If a pure substance can be decomposed into simpler substances, it is a compound. • If a substance cannot be decomposed into simpler substances, it is an element. • Mixtures are composed of two or more pure substances in proportions that may vary. • If the mixture appears uniform to the eye, it is homogeneous. If it is nonuniform, it is heterogeneous.
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Measurement and the Metric System
Chapter 1 Summary Measurement and the Metric System • The modern metric system is called the SI system whose base units are the kilogram, meter, and second. • Units of the older metric, or non-SI, system are the gram, centimeter, and second. • Very large and very small quantities in the SI system are simplified by the use of prefixes denoting multiples of ten.
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Uncertainty and Significant Figures
Chapter 1 Summary Uncertainty and Significant Figures • The last digit in any measurement is an estimate, and therefore, is an unavoidable uncertainty or variability. • The degree of uncertainty is expressed by employing the concept of significant figures.
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Chapter 1 Summary Scientific Notation
• In scientific notation, a number is expressed as a coefficient (a number between 1 and 10) multiplied by an exponential factor (10 raised to a whole-number power). • Numbers expressed in scientific notation are added or subtracted by converting all exponents into the same value. The exponents are then added in multiplication and subtracted in division.
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Calculations and Significant Figures
Chapter 1 Summary Calculations and Significant Figures • The number of significant figures in a calculated quantity cannot be greater than the smallest number of significant figures in any of the measured quantities.
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Fundamental Properties of Matter
Chapter 1 Summary Fundamental Properties of Matter • The mass of an object is the quantity of matter in that object. • Volume is the amount of space that the object occupies. It is the product of three linear dimensions and is therefore a derived quantity. • Density is defined as mass divided by volume and is determined by measuring the mass of a given volume of a substance. • The density of a liquid or a solution can also be measured by its effect on the buoyancy of a float called a hydrometer.
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Chapter 1 Summary Heat and Calorimetry
• The concept of temperature allows us to quantitatively specify how hot or cold an object is. • There are three temperature scales: the Celsius, Kelvin, and Fahrenheit scales. • Heat is determined in a calorimeter by measuring the change in temperature undergone by a given mass in response to the addition or loss of heat. • Human basal metabolic rates can be determined directly by calorimetry or, more often, indirectly by oxygen consumption.
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