<span>When a substance changes from one state, or phase, of matter to another we say that it has undergone a change of state, or we say that it has undergone a change of phase. For example, ice melts and becomes water; water evaporates and becomes water vapor.These changes of phase always occur with a change of heat. Heat, which is energy, either comes into the material during a change of phase or heat comes out of the material during this change. However, although the heat content of the material changes, the temperature does not.</span>
Answer:
Mass = 547.02 × 10⁻²³g
Explanation:
Given data:
Number of atoms of Al = 122 atom
Mass in gram = ?
Solution:
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
122 atom/6.022 × 10²³ atoms × 1 mol
20.26× 10⁻²³ mol
Mass in gram:
Mass = number of moles × molar mass
Mass = 20.26× 10⁻²³ mol × 27 g/mol
Mass = 547.02 × 10⁻²³g
Answer:
This question is incomplete
Explanation:
This question is incomplete because of the absence of the drawing referred to in the question.
However, each option refers to a particular respiratory system and with the organs and the tissues mentioned here one can eventually identify which option is correct when the drawing is available.
A) The system described here is the cardiovascular system (or the circulatory system). This system involves the heart, blood vessels and the blood (which are what help in the transport of the materials mentioned in the question).
B) The system described here is the digestive system. This system involves the gastrointestinal tract and organs (that assist in the production/secretion or storage of chemicals that breakdown food into smaller pieces) such as the mouth, esophagus, stomach, small intestine, large intestine, rectum and the anus.
C) The system described here is the skeletal system. This system involves all the bones and joint in the body (the skeleton) which also helps in protecting organs in the body.
D) The system described here is the Endocrine system. This system involves several internal glands (such as the thyroid gland and the adrenal glands) in the body.
NOTE: Identify which organ and/or tissue is present in the diagram and use that to select the appropriate option from the description of each of the options provided above.
Answer:
B. Conclusions are based on observations
Explanation:
Answer:
2.77 mL of boiling water is the minimum amount which will dissolve 500 mg of phthalic acid.
Explanation:
We know from the problem that 18 g of phthalic acid are dissolved in 100 mL of water at 99 °C.
Now we devise the following reasoning:
If 18 g of phthalic acid are dissolved in 100 mL of water at 99 °C
Then 0.5 g of phthalic acid are dissolved in X mL of water at 99 °C
X = (0.5 × 100) / 18 = 2.77 mL of water
