A. neutrons
Isotopes <span>contain equal numbers of protons but different numbers of neutrons in their nuclei.</span>
Answer:
54.1 % Ca, 43.2 % O, 2.7% H
Explanation:
Molecular formula for calcium hydroxide is Ca(OH)₂
As we don't have a mass of Ca(OH)₂ to find out the percentage composition, we consider that the question refers to 1 mol of compound.
1 mol of hydroxide weighs 74.08 g
1 mol of hydroxide has 1 mol of Ca, therefore 40.08 g are Ca
2 moles of O therefore 32g are O
2 moles of H therefore 2 g are H
Percentage composition is known as (Mass of element/Total mass) . 100
- (40.08 / 74.08) . 100 = 54.1 %
- (32 / 74.08) . 100 = 43.2 %
- (2 / 74.08) . 100 = 2.7%
Answer:
2. 14
Explanation:
To form Br₂ bond, a total of 14 electrons are needed.
Bromine is an element in the 7th group on the periodic table. It has 7 valence electrons.
- In forming the bromine gas, the two atoms of bromine shares 7 electrons each.
- These electrons are from their outermost shell.
- The outermost shell is the valence shell.
- So, two atoms donating 7 electrons gives 14 electrons.
Answer:
5.81L
Explanation:
N1 = 1.70 moles
V1 = 3.80L
V2 = ?
N2 = 2.60 moles
Mole - volume relationship,
N1 / V1 = N2 / V2
V2 = (N2 × V1) / N1
V2 = (2.60 × 3.80) / 1.70
V2 = 9.88 / 1.70
V2 = 5.81 L
The volume of the gas is 5.81L
Answer:
Cells divide to reproduce. There are two primary methods used, one for somatic cells, which compose the organism’s body, and one for reproductive cells, or gametes.
Scientists call the process of somatic cell division mitosis. Mitosis has six distinct steps in which the cell organizes and copies the DNA in the nucleus. Once copied, each new cell has its own copy of the DNA. The six steps of mitosis are prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis. Some authorities consider the non-dividing portion of the cell’s lifecycle, known as interphase, to be one of seven steps involved in mitosis; however, interphase cells are not actively dividing.
Sex cells, such as sperm or eggs, must divide differently. Sex cells only possess one-half of the DNA that makes up a new animal. That way, when they combine, the resulting organism gets half of its DNA from its mother and half from its father. Because sex cells only want half of the DNA in each cell, they go through a different division process called meiosis. In meiosis, the cells split a second time, which yields four daughter cells rather than two as with mitosis; however, this provides each daughter cell with 23 chromosomes in contrast to the 46 chromosomes in somatic cells.
