Answer:
1. The standard metric unit of length is a meter.
2. A proposed explanation for a scientific problem is a hypothesis.
3. The standard unit of volume is a liter.
4. The curved top surface of a liquid column is the meniscus.
5. A quantity in an experiment that remains unchanges or constant is a controlled variable (control)
6. The amount of matter in an object is mass.
Answer:
The pressure of the gas increased (if temperature remained constant).
The Boyle's law supports this observation.
Explanation:
The initial measurements of the gas are given as;
volume = 100 L
Pressure = 300 kpa
The second measurement is given as;
Volume = 75 L
The second reading implies that the volume of the gas has decreased. If the temperature of the gas remained constant, then the pressure must have increased according to the Boyle's law;
At constant temperature, the pressure of a given mass of an ideal gas is inversely proportional to its volume.
49 neutrons in each nucleus.
<h3>Explanation</h3>
For each nucleus:
Mass number = Number of protons + Number of neutrons.
The atomic number of a nucleus is the same as its number of protons. The atomic number of the nucleus here is 31. There are 31 protons in each nucleus.
- Mass number = 80;
- Number of protons = Atomic number = 31;
- The number of neutrons is to be found.
Again,
Mass number = Number of protons + Number of neutrons.
80 = 31 + Number of neutrons.
Number of neutrons = 80 - 31 = 49.
