Answer:
I want to say option C: Testing which surfa e is easier to slide a wooden block across.
Explanation:
I'm not 100 % sure though with my answer. I'm truly so very sorry if my answer is wrong. I tried my best.
Answer:
1)Krypton
2)11H
Explanation:
electrons=protons
protons=atomic number
mass number=protons+neutrons
mass number is the superscript
atomic number is the subscript.
1)The answer is Krypton because its atomic number= number of protons=number of electrons is 36.
mass number is 46+36=82.
2)subscript=atomic number=number of protons=number of electrons
i. H = electrons=1
=neutrons=0
ii. Cl=electrons=17
=neutrons=35-17=18
iii. Na=electrons=11
=neutrons=23-11= 12
so the answer is Hydrogen because it has 1 electron and 0 neutron.
I hope this helps.
Answer: A. Limestone rocks dissolving in water
Explanation:
B: This is a physical change; it changes an object physically rather than chemically. It does not change the composition of the concrete, only the shape.
C: This is also a physical change because the water is just dragging sand with it, but not actually changing the composition of it.
D: Similar to option B, this is an example of physical weathering because the ice only divides the rock into different parts but doesn't change the composition or complexity of it.
Answer:
(1). The vapor pressure is 91 mmHg at 20°C.
(2). No, benzene will not boil at sea level.
Explanation:
Benzene, C6H6 is an aromatic, liquid compound with with molar mass of 78.11 g/mol and Melting point of 5.5 °C. One of the importance or the uses of benzene is in the making of fibres and plastics.
The vapour pressure of benzene can be gotten from the table showing the vapor pressure of different liquids.
Boiling point can simply be defined as the point or the temperature in which the vapor pressure is the same with the atmospheric pressure.
The atmospheric pressure is 760mmHg, while the vapor pressure at sea level is at the temperature of 15°C which is equal to 71 mmHg( from the table showing the vapor pressure of different liquids).
71 mmHg is not equal to 760 mmHg, thus, at sea level Benzene will not boil.