Nitrogen. air consists 78% of nitrogen gas
Explanation:
Physical change -
It refers to any change during any process , where there is no new substance is formed , is referred to as a physical change.
Any change in the state of matter is characterised under physical change.
Chemical change -
It refers to any change in a chemical process , where there is formation of any new substance , is referred to as a chemical change .
From the options given in the question,
1. Apple turning brown , on air exposure , is an example of chemical change .
2. The physical state of mercury is liquid , is an example of physical change .
3. phosphorus burns on exposed to air , is an example of chemical change .
4. The gas Neon is colorless at the room temperature , is is an example of physical change .
Answer:
1. The correct option is;
c. maintains charge balance in the cell
2. The correct option is;
c. +3.272 V
Explanation:
The aqueous solution in a galvanic cell is the electrolyte which is a ionic solution containing that permits the transfer of ions between the separated compartment of the galvanic cell such that the overall system is electrically neutral
Therefore, the aqueous solution maintains the charge balance in the cell
2. Here we have;
B₂ + 2e⁻ → 2B⁻ Ecell = 0.662 V
A⁺ + 1e⁻ → A Ecell = -1.305 V
Hence for the overall reaction, we have;
2A + B₂ → 2AB gives;
(0.662) - 2×(-1.305) = +3.272 V.
Answer:
Spindle fibers form.
DNA condenses into chromosomes.
Explanation:
Prophase is the first stage of mitosis. Mitosis produces 2 daughter cells from a parental cell.
Spindle fibers form - this is true. During prophase, the mitotic spindle forms. Later during mitosis the spindle attaches to the centromere of chromosomes and pulls them to opposite ends of the cell prior to division
DNA condenses into chromosomes. - this is true. In the nucleus during interphase, the DNA is relatively loosely compacted. However, prior to division, the DNA is condensed into structures called chromosomes which are then paired up and distributed to the daughter cell.
Chromosomes move to opposite ends of the cell. - this is false. This happens during anaphase
Nuclear membrane begins to re-form. - this is false. This happens during telophase.
