Understanding Physical Quantities and States of Matter

1. True or False Statements

a) True

b) True

c) True / FALSE, if the hypothesis has not been demonstrated.

2. Measurement Units and Properties

a) Size: m³ is a unit of volume and can be used in moderation.

b) Scalability: It does not scale; it is not a unit of restraint.

c) Magnitude Measurement: Magnitude can be measured in K (Kelvin).

3. Units of Measurement

• Length - Meter - m
• Mass - Kilogram - kg
• Time - Second - s
• Temperature - Kelvin - K
• Intensity of Current - Ampere - A

4. Unit Conversions

a) 2.5 mm x (1 m / 1,000 mm) = 0.0025 m = 2.5 x 10^-3 m

b) 0.53 mg x (1 g / 1,000 mg) x (1 kg / 1,000 g) = 0.00000053 kg = 5.3 x 10^-7 kg

c) 3 h x (3,600 s / 1 h) = 10,800 s = 1.08 x 10⁴ s

5. Calculations with Significant Figures

a) 8.34 x 3.1456 = 26.234304 = 26.2

b) 4.00 / 0.325 = 12.307692 = 12.3

6. Error Analysis

a) The error percentage is not relative; it is expressed in absolute units. It is expressed with the same units as the measurement, used sparingly.

b) To determine this, the relative error must be estimated: e_r = (15 cm / 160 cm) x 100 = 9.3% < 10%: it is a good measurement.

7. Measurements with Uncertainties

a) Measurement: (95 ± 5) mm

b) Measurement: (5.6 ± 0.1) cm³

c) Measurement: (12 ± 1) kg

d) Measurement: (3.4 ± 0.1) V

e) Measurement: (54 ± 1) ºC

8. Precision and Significant Figures

The rule that gives a measurement of 1.20 m is more precise because it is sensitive to a precision of ± 0.01 m, while at 1.2 m, the precision is ± 0.1 m. The first measurement has three significant figures, and the second has only two.

9. Diameter Calculation and Error Analysis

a) Average Diameter = (0.87 + 1.01 + 1.10 + 0.95 + 0.91) / 5 = 0.968 = 0.97 mm

b) Absolute Errors: E_A1 = 0.10 mm; E_A2 = -0.04 mm; E_A3 = -0.13 mm; E_A4 = 0.02 mm; E_A5 = 0.06 mm. Measurement = (0.97 ± 0.13) mm

c) Relative Error: e_r = (0.13 mm / 0.97 mm) x 100 = 13.40%

10. States of Matter

• Solid: Constant shape and volume.
• Liquid: Constant volume, variable shape.
• Gas: Variable volume and shape.

11. Properties of Gases

• When we heat a gas, its particles move faster. - True
• The particles of a gas move in a specific direction. - FALSE, the movement is disordered.
• The interaction forces in solids are weaker. - FALSE, the forces are stronger in solids.

12. Pressure in Gases

The particles in a gas move in all directions and can collide with each other and with the walls of the container. The collisions with the walls cause the pressure.

13. Diffusion and Compressibility of Gases

a) Gas particles are in continuous motion. Therefore, when the particles of one gas are introduced into another, they will diffuse between those of the other gas, following their chaotic movement.

b) Gases can be compressed more easily because pressure can be applied to reduce the distance between particles. When the pressure is released, the particles will move apart, occupying the maximum possible volume.

14. Matching Concepts

1-6, 2-1, 3-2, 4-4, 5-3, 6-5

15. Temperature and States of Matter

• False, the melting point is not equal to the boiling point.
• False, the temperature remains constant during a change of state, regardless of whether it is heated more or less rapidly.

16. States of Matter at Different Temperatures

• -40ºC: Solid
• -10ºC: Liquid
• 10ºC: Liquid
• 40ºC: Gas

17. Condensation in a Refrigerator

When warm, humid air comes into contact with the cold interior of the refrigerator, the water vapor condenses, forming water droplets or ice.