Answer:
d. Equinox
Explanation:
A certain day in spring and autumn where the amount of daytime hours and nighttime hours are the same is called equinox.
Equinox occurs twice in a year on March 20 and September 23rd.
- During an equinox, the south and north hemisphere of the earth are receiving equal amount of sunlight.
- The opposite of equinox is solstice in which the duration of light is unequal.
- The equator is the only great circle that is a line of latitude.
Molality is the moles of solute per kg of solvent.
Moles of NH₄Cl = 2.4 / (14 + 4 x 1 + 35.5)
= 0.0448 mole
Molality = 0.0448 / (19.4 / 1000)
= 2.31 m
Answer:
All living things are made up of cells.
cells are the basic unit of structure and function of ll living things.
All cells are come from other cells.
Explanation:
The cell theory is historic scientific theory and is universally accepted. This theory was given by Robert Hook in 1665. According to this theory all living things are made up cells.
Cell:
Cell is the smallest unit of life and it is building block of life.
This theory consist of following points:
All living things are made up of cells.
Cells are the basic unit of structure and function of ll living things.
All cells are come from other cells. Which means that cells are originated from pre-existing cells.
The other given options:
Cells comes from nonliving matter.
Cells make up most organisms bu not all.
These are two are not the postulate of cell theory because all living organisms are made of cells.
The three states of matter<span> are the </span>three<span> distinct physical forms that </span>matter<span> can take in most environments: solid, liquid, and gas. In extreme environments, other </span>statesmay be present, such as plasma, Bose-Einstein condensates, and neutron stars. Courtesy of <span>https://www.boundless.com/chemistry/...matter.../three-states-of-matter-178-10543/</span>
Answer:
B. PCl₅ → PCl₃ + Cl₂.
Explanation:
- The conservation of mass is a phenomena that is applicable and found in chemical reaction but only balance chemical reactions.
- Balanced chemical reaction means that: The number of atoms of the reactants = the number of atoms in the products.
- In balanced chemical reaction; the atoms that enter and participate in the reaction will result from it and maintain the mass of each atom.
- The first choice (A) is wrong that it is unbalanced chemical reaction,
H₂O → H₂ + O₂, the oxygen has 1 atom in the reactants side while has 2 atoms in the products side.
to be balanced and apply conservation of the mass it should be: H₂O → H₂ + 1/2O₂.
- The second choice (B) is the right answer: PCl₅ → PCl₃ + Cl₂.
The number of atoms of P (1 atom) and Cl (5 atoms) are the same in both sides of reactants and products.
- The third choice (C) is wrong that it is unbalanced chemical reaction,
Na + Cl₂ → NaCl, the Cl has 2 atoms in the in the reactants side while has 1 atom in the products side.
to be balanced and apply conservation of the mass it should be: Na + 1/2Cl₂ → NaCl.
- The fourth choice (D) is wrong that it is unbalanced chemical reaction,
Al + Br₂ → AlBr₃, the Br has 2 atoms in the in the reactants side while has 3 atoms in the products side.
to be balanced and apply conservation of the mass it should be: 2Al + 3Br₂ → 2AlBr₃.