Which of these materials is a substance? th
А.
1.
A. air
C. sea water
sea of clouds
B. pure water
D
Which of the following statements distinguishes pure substance from
2.
mixture?
A. can be separated by physical means
B. Consists of two or more kinds of matter
C. Have no specific solubility and densities
D. Have constant boiling temperature and melting temperature,
3. What is the process of separating the components Hydrogen and
Oxygen in water?
А.
electrolysis
electrification
C.. hydrolysis
D. hydrophonics
B.
4. Which of these materials can be separated physically?
A. carbon dioxide
C. water
B. salt and water
D. salt
Refer to the statement below to answer questions 5-6.
Matthew tested the melting point of a certain sample of potassium
alum/tawas. His records showed that it start melting at 91°C and melted
completely until the temperature is 92.5°C. He referred his observations
from a data that says the melting point of potassium alum is 92.5°C.
5. From the observations made, Matthew can say that Potassium alum is
a pure substance.
A. correct
B. Incorrect
6. Which of these temperature readings would prove your answers to
questions number 57
A. 91°C
C. 92.5°C
B. between 91°C to 92.5°C D. above 92°C
7. Which of these describes a pure substance?
A. it appears homogeneous
B. A solid pure substance melts completely
C. A liquid pure substance has a fixed boiling point
D. All of these