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General Chemistry at the University of Oklahoma Exam 1 University of Oklahoma Chemistry

315 vues•102 diapositives

- 1. One-School.net 1 Introduction to Physics I Understanding Base and Derived Quantities Physical Quantity 1. A physical quantity is a quantity that can be measured. 2. Physical quantities are usually expressed as the product of a numerical value and a physical unit Example 2 2.34 10 E kJ = × where • E represents the physical quantity of energy • 2 2.34 10 × is the numerical value • k is the SI prefix kilo representing 103 • J is the symbol for the unit of energy, the joule 3. A physical quantity can be divided into base quantity and derived quantity. Base quantity 1. Base quantities are the quantities that are conventionally accepted as functionally independent of one another. 2. It is a quantity that cannot be defined in term of other physical quantity. 3. The base Quantities and its units are as below: Quantity Name of unit Unit symbol Length metre m Mass kilogram kg Time second s Electric current ampere A Thermodynamic temperature Kelvin K Amount of substance mole mol Luminous intensity candela cd [Notes: Amount of substance and Luminous intensity are not discussed in SPM physics syllabus.] The SI base units are defined as follows: Unit Definition metre The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second. kilogram The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram. second The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom. ampere The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2 × 10−7 newton per metre of length. kelvin The Kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water. mole The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles. [Notes: The definitions of the units are only served as an additional note, it is not discussed in the SPM syllabus.]
- 2. One-School.net 2 Exercise 1 1. Which of the following quantity is not a base quantity? A Length B Mass C Current D Force 2. Which of the following quantity is base quantity? A Temperature B Force C Volume D Charge 3. Which of the following units is not a SI base unit? A Kelvin B Newton C Kilogram D Ampere 4. The unit of mass which defined in SI system is A Gram B Kilogram C Pound D Kilopound 5. Which of the following is true? kilogram gram A Multiple of base unit Multiple of base unit B Base unit Base unit C Multiple of base unit Base unit D Base unit Multiple of base unit Answer Scientific notation (Standard form) 1. Scientific notation (also known as Standard index notation) is a convenient way to write very small or large numbers. 2. In this notation, numbers are separated into two parts, a real number with an absolute value between 1 and 10 and an order of magnitude value written as a power of 10. 3. Physical quantities that are very big or very small need to be written in the standard form so that it is neat, simple and easy to read. Example: Numerical value Standard form 6 020 000 000 000 000 kg 0.000 000 000 074 m Significant Figure 1. In measurement, significant figures relate the certainty of the measurement. 2. As the number of significant figures increases, the certainty of the measurement increase, which means we are more certain about what we have measured.
- 3. One-School.net 3 3. In the SPM syllabus, the magnitude of a physical quantity is usually rounded up to 3 or 4 significant figures. Example: speed of light in a vacuum = 299 792 458 ms-1 = 3.00 × 108 ms-1 (to 3 significant figures) Exercise 2 1. Write down the significance figure (s.f.) of the following value: a. 135 m, (____s.f.) b. 0.013s (____s.f.) c. 0.2000A (____s.f.) d. 25.10 g (____s.f.) e. 3700km (____s.f.) f. 0.003kg (____s.f.) g. 1.54 × 10-3 (____s.f.) i. 0.001200 (____s.f.) 2. Round up the following number to the number of significance figure (s.f.) that given in the bracket. a. 235478 [3s.f.] b. 230008 [3s.f.] c. 12.4369 [4s.f.] d. 0.00216 [1s.f.] e. 134.016 [2s.f.] Prefixes Prefixes are the preceding factor used to represent very small and very large physical quantities in SI units. Prefixes Value Standard form Symbol Tera 1 000 000 000 000 1012 T Giga 1 000 000 000 109 G Mega 1 000 000 106 M Kilo 1 000 103 k deci 0.1 10-1 d centi 0.01 10-2 c milli 0.001 10-3 m micro 0.000 001 10-6 μ nano 0.000 000 001 10-9 n pico 0.000 000 000 001 10-12 p Conversion of prefixes Prefixes to Numerical Value Example 1 The frequency of the radio wave is 210M Hz. What is the frequency of the radio wave in Hz? Example 2 The thickness of a film is 245nm. What is the thickness in unit meter? Numerical Value to Prefixes Example 3 0.306 s is equal to how many ms. Example 4 Convert 0.00034W into µW.
- 4. One-School.net 4 Prefixes to Prefixes Example 5 Convert 0.000012 km into cm. Example 6 Convert 630,000,000 J into kJ. Example 7 Arrange the following values in ascending order. 3 2.32 10 Mm − × 4 2.32 10 cm × 7 2.32 10 m μ × 4 2.32 10 km − × Answer 3 2.32 10 Mm − × = 7 2.32 10 m μ × = 4 2.32 10 cm × = 4 2.32 10 km − × = Units for Area and Volume Example 8 a) 7.2 m = ____________cm b) 0.32 m2 = ____________cm2 c) 0.0012 m3 = ____________cm3 d) 5.6 cm = ____________m e) 350 cm2 = ____________m2 f) 45000 cm3 = ____________m3 Exercise 3 1. Convert each of the following measurements into metre ( m ). a) 12000 μm b) 230 mm c) 0.34 km d) 0.012 Mm 2. Complete the following unit convertion a) 12.34 kHz = ___________ Hz b) 120 Mm = ___________m c) 0.12 μg = ___________g d) 7.1×103 mJ = ___________J e) 8.34×10-1 cA = ___________A f) 5.1×102 dW = ___________W g) 1.11×10-3 nm = ___________m h) 7.134 ×104 pm= ___________m i) 14500 g = ___________kg j) 12.34 N = ___________MN k) 0.134 s = ___________ ms l) 756.6 Hz = ___________ kHz m) 0.00034 J = ___________ μJ n) 3.12 A = ___________d A o) 134 kg = ___________mg p) 1117 nHz = ___________μHz q) 0.230 km = ___________μm r) 0.012 MJ = ___________kJ 1 m = ______ cm 1 m2 = ______ cm2 1 m3 = ______ cm3 1 cm = ______ m 1 cm2 = ______ m2 1 cm3 = ______ m3 1 m = 100cm 1 m2 = 1m × 1m = 100cm × 100cm = 10 000 cm2 = 1 × 104 cm2 1 m3 = 1m × 1m × 1m = 100cm × 100cm × 100cm = 1 000 000 cm3 = 1 × 106 cm3
- 5. One-School.net 5 3. Complete the following unit conversion a) 13 m = ____________cm b) 12.1 m2 = ____________cm2 c) 0.1 m3 = ____________cm3 d) 12.1 cm = ____________m e) 1200 cm2 = ____________m2 f) 130 cm3 = ____________m3 g) 3.55 m2 = ____________cm2 h) 1200 m2 = ____________cm2 i) 1000 m3 = ____________cm3 j) 1.2×102m3 = ____________cm3 k) 5.34×105cm2 = ____________m2 l) 7230 cm2 = ____________m2 m) 9.8×10-1cm3 = ____________m3 n) 800 cm3 = ____________m3 o) 7×10-3 cm = ____________m 4. Which of the following sets of prefixes are arranged in descending order? A mili, centi, micro B mega, micro, gega C kilo, mili, centi D kilo, mili, nano 5. Which of the following length is the longest? A 7.1×103 cm B 6.4×105 μm C 4.2×10-3 km D 9.8×10-7 Mm 6. Which of the following unit conversions is not correct? A 230 Ms = 2.3 × 108 s B 360 μs = 3.6 × 10-4 s C 0.0013s = 1.3 ms D 2.34 × 105 s = 23.4 ks 7. Among the quantity below, which one is equivalent to 0.000360 m? A 360 km B 360 cm C 360 mm D 360 µm 8. 0.34km is equivalent to A 3.4 × 104 cm B 3.4 × 10-3 Mm C 3.4 × 106 mm D 3.4 × 103 m 9. The standard form of 540μK is A 5.40 × 102 K B 5.40 × 10 K C 5.40 × 10-6 K D 5.40 × 10-3 K E 5.40 × 10-4 K 10. Which of the following unit conversions is correct? A 2.5 m2 = 250 cm2 B 5.6 m3 = 560 cm2 C 4500 cm2 = 45 m2 D 2.5 × 107 cm3 = 25 m3 11. The dimension of cuboids is 20cm, 25cm and 30cm. The volume of the cuboids is. A 1.5 × 10-2 m3 B 1.5 m3 C 1.5 × 102 m3 D 1.5 × 104 m3 12. The dimension of cuboids is 10cm, 20cm and 20cm. The total surface area of the cuboids is. A 1600 m2 B 16 m2 C 1.6 m2 D 0.16 m2 Answer 1. 4. 7. 10. 2. 5. 8. 11. 3. 6. 9. 12. Derived Quantity 1. A derived quantity is a Physics quantity that is not a base quantity. It is the quantities which derived from the base quantities through multiplying and/or dividing them. Example Area of a rectangle = length of the rectangle × width of the rectangle 2. The length and width of the rectangle are base quantity whereas the area of the rectangle is a derived quantity. It is derived from the product of two base quantities.
- 6. One-School.net 6 Example State whether the following quantities in the equation are base or derived quantity. Equation Quantity Distance = ___________ quantity Time = ___________ quantity Time Distance Speed = Speed = ____________ quantity Example of derived quantities Quantity Equation Unit Unit symbol Area Area = length × width square metre m2 Volume Volume = length × width × height cubic metre m3 Frequency 1 frequency period = hertz Hz s−1 Density mass density volume = kilogram per cubic metre kg m−3 Velocity/speed displacement velocity time = metre per second m s−1 Acceleration velocity change acceleration time = meters per second squared m s−2 Force Force = mass × acceleration Newton N m kg s−2 Pressure, stress force pressure area = Pascal Pa N m−2 Energy, work Work = force × displacement Joule J N m Power work power time = Watt W J s−1 Quantity of electricity Quantity of charge = current × time Coulomb C A s Potential difference, electromotive force arg energy potential difference ch e = Volt V WA−1 Electric resistance potential difference resistance= current Ohm Ω VA−1 Unit A unit is a particular physical quantity, defined and adopted by convention, with which other particular quantities of the same kind are compared to express their value. SI unit The International System of Units (abbreviated SI from the French language name Système International d'Unités) is the modern form of the metric system. It is the world's most widely used system of units, both in everyday commerce and in science.
- 7. One-School.net 7 Example 6 Which of the physical quantity below has correct S.I. unit? Physical Quantity S.I. unit A Length Centimeter B Mass Gram C Time Minute D Current Ampere Derived Unit 1. The derived unit is a combination of base units through multiplying and/or dividing them. For instance, Speed is defined as the rate of distance change, and can be written in the mathematic form Time Distance Speed = The base unit for distance (length) is metre (m) and The base unit for time is second (s). Therefore, The unit of speed 1 ( ) ( ) m ms s − = = 2. Sometime, the units are named after great physicist to honour their significant contributions to the field of physics. 3. For example Newton, N, which is the unit of force, is named after Sir Isaac Newton, who contributed a lot to the classical mechanic. Find the derived unit Example 7 Derive the units for the following quantities a) Acceleration b) Density c) Work d) Charge e) Potential difference Hint velocity change acceleration time = mass density volume = Work = force × displacement Quantity of charge = current × time arg energy potential difference ch e = Example 8 The moment inertia of a disc is given by equation 2 2 1 mr I = m = mass of the disc and r = its radius. Find the unit of moment inertia, I. Find the unit of a constant in an equation Example 9 The relationship of the mass of a metal plat with its area is given by the equation mass = k × area What is the unit of k?
- 8. One-School.net 8 Unit conversion Example 9 A car is moving with speed 2km minute-1 , what is the speed in m s-1 ? Example 10 Complete the following unit conversion a) 12 kmh-1 = __________ ms-1 b) 12 ms-1 = __________ kmh-1 c) 12 kgm-3 = __________ gcm-3 d) 0.2 gcm-3 = __________ kgm-3 e) 0.000012 kg m s-2 = _________g cm s-2 Convert the SI unit to its base unit Write the following unit in an appropriate base unit: a) 3 J = b) 2 N= Summary Physical quantities A physical quantity is a quantity that can be measured. Base quantity Base quantities are the quantities that are conventionally accepted as functionally independent of one another. Derive Quantity A derived quantity is a Physics quantity that is not a base quantity. It is the quantities which derived from the base quantities. Unit A unit is a particular physical quantity, defined and adopted by convention, with which other particular quantities of the same kind are compared to express their value. Exercise 4 1. Which of the followings is a derived quantity? A Charge B Current C Temperature D Length 2. Which of the following quantities is not derived from the base quantity of time? A Force B Density C Pressure D Speed 3. Which of the followings is a derived unit? A metre2 B Kelvin C gram D second 4. Which of the following is not a derive unit? A Newton B Kelvin C Watt D Joule
- 9. One-School.net 9 5. Which of the derived units below is correct for the given quantities? displacement velocity acceleration A ms-2 m ms-1 B m ms ms-2 C m ms-2 ms-1 D m ms-1 ms-2 6. The unit of force, Newton (N) is equivalent to A kg ms-1 B kg m2 s-2 C kg ms-2 D kg2 ms-2 7. The derived unit kg s-2 is equivalent to A N m-1 B g s-1 C kg s-1 D N cm-2 8. Which of the following is the unit of density? [Hint: mass density volume = ] A kg m3 B kg m2 C kg m-3 D kg m-2 9. Which of the following derived units is wrong? Derived Quantity S.I. unit A Acceleration ms-2 B Density kg m-3 C Pressure kg m-2 D Work kg m2 s-2 10. Given that the mass and the volume of an ice cube is as below Mass = 0.45kg Volume = 500 cm3 Find the density of the ice in kg m-3 . [Notes: mass density volume = ] 11. The relationship of pressure (P), force (F) and area (A) is given by the equation F P A = . Find the value of pressure when the force = 500N and the area = 10000 cm2 . 12. The elastic potential energy (US) that store in a spring is given by the formula 2 1 2 s U kx = , where k is the coefficient of the spring and x is the extension of the spring. The unit of k is A J m-1 B kg s-2 C J m2 D kg m2 s-2 13. The specific heat capacity of a substance (c) if given by the equation E c mθ = Where E = heat change (Energy) m = mass of substance θ = temperature change Find the unit of specific heat capacity, c A J kg K-1 B J kg-1 K C J kg K-2 D J kg-1 K-1
- 10. One-School.net 10 14. Find the unit of following Derive quantity. a) Acceleration ( velocity change time taken acceleration = ) b) Momentum (momentum = mass × velocity) c) Impulse (impulse = change of momentum) d) Density ( mass density volume = ) e) Force (Force = mass × acceleration) f) Pressure ( force pressure area = ) g) Electric Charge (electric charge = current × time) 15. Complete the following unit conversion of speed. a) 90 kmh-1 = __________ ms-1 b) 110 kmh-1 = __________ ms-1 c) 1.3 ms-1 = __________ kmh-1 d) 8.12 ms-1 = __________ kmh-1 16. Complete the following unit conversion of density. a) 760 kgm-3 = __________ gcm-3 b) 12000 kgm-3 = __________ gcm-3 c) 5.1 gcm-3 = __________ kgm-3 d) 3600 Nm-2 = __________ Ncm-2 e) 12×106 Nm-2 = __________ Ncm-2 f) 1.5×10+ Nm-2 = __________ Ncm-2 g) 3.16×10-5 Ncm-2 = __________ Nm-2 h) 7.1×10-3 Ncm-2 = __________ Nm-2 17. Convert 4500kJ/hour to Watt (J/s). A 1250 W B 1.25W C 75W D 75 000W