Answer:
6. 7870 kg/m³ (3 s.f.)
7. 33.4 g (3 s.f.)
8. 12600 kg/m³ (3 s.f.)
Explanation:
6. The SI unit for density is kg/m³. Thus convert the mass to Kg and volume to m³ first.
1 kg= 1000g
1m³= 1 ×10⁶ cm³
Mass of iron bar
= 64.2g
= 64.2 ÷1000 kg
= 0.0642 kg
Volume of iron bar
= 8.16 cm³
= 8.16 ÷ 10⁶
Density of iron bar
= 7870 kg/m³ (3 s.f.)
7.
Mass
= 1.16 ×28.8
= 33.408 g
= 33.4 g (3 s.f.)
8. Volume of brick
= 12 cm³
Mass of brick
= 151 g
= 151 ÷ 1000 kg
= 0.151 kg
Density of brick
= mass ÷ volume
(3 s.f.)
the mass number of fluorine (F) is 19
C. 19
Answer ; The correct answer is : 346 m/s .
Sound is a type of longitudinal wave , which is produced when a matter compress or refracts .
Speed of sounds depends on factors like medium , density , temperature etc .
Effect of Temperature on speed of sounds :
When the temperature increases , molecules gains energy and they starts vibrating and with higher temperature vibration becomes fast . So the waves of sounds can travel faster due to faster vibrations . Hence , speed of sounds is directly proportional to the temperature or speed of sounds increases with increase in temperature .
The speed of sounds at 0⁰C is 331 
The relation between speed of sound and temperature is given as :
Given : Temperature = 25 ⁰ C
Plugging values in formula =>
It is 79 - + 3 = 76 electrons.
Answer:
A sample of an ideal gas has a volume of 2.21 L at 279 K and 1.01 atm. Calculate the pressure when the volume is 1.23 L and the temperature is 299 K.
You need to apply the ideal gas law PV=nRT
You have the pressure, P=1.01 atm
you have the volume, V = 2.21 L
The ideal gas constant R= 0.08205 L. atm/ mole.K at 273 K
find n = PV/RT = (1.01 atm x 2.21 L / 0.08205 L.atm/ mole.K x 273 K)
n= 0.1 mole, Now find the pressure for n=0.1 mole, T= 299K and
L=1.23 L
P=nRT/V= 0.1mole x 0.08205 (L.atm/ mole.K x 299 k)/ 1.23 L
= 1.994 atm
Explanation:
