Answer:
Explanation:
The following are the order of point from oldest to most recent
1. Atoms are tiny indivisible particles that make up all mater.
it is Postulate of Dalton's atomic theory. this theory was put forward in 1803
2. Negatively charged electrons are embedded in a mass of positive charge.
In 1897 J.J Thomson discovered that atom consist of tiny negatively charged particles called electrons that are uniformly spread in +vely charged matrix this model called as plum pudding model.
3. Atoms consist of mostly empty space with a dense nucleus of positive charge.
While doing experiment on gold foil Rutherford presented a model in 1909 and stated that atom consist mostly empty space with dense nucleus.
4. Electrons occupy specific energy levels surrounding a positively charged nucleus.
Niels Bohr in 1913 put forward a model to explain atomic orbitals/energy level. This is a postulate of Bohr model.
5. Electrons move about a positively charged nucleus in clouds that are defined by probabilities.
In 1926 Erwin Schrödinger explain the wave function of electrons and its probability.
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6a. physical reaction
6b. endothermic reaction
7a. physical reaction
7b. the reactants are carbon dioxide, water and light energy. the product is starch
7c. exothermic reaction
Answer:
142.36 kg
Explanation:
volume of water in the lake = surface area x depth
= 18.5 x ( 1760 x 3 )² x 39 ft³
= 2.011 x 10¹⁰ ft³
= 2.011 x 10¹⁰ x 28.3168 liter .
= 56.945 x 10¹⁰ liter .
concentration of mercury = .25 x 10⁻⁶ g / liter
= 25 x 10⁻⁸ g / liter
= 25 x 10⁻¹¹ kg / liter
mass of mercury in the water of lake
= 25 x 10⁻¹¹ x 56.945 x 10¹⁰ kg
= 142.36 kg .
Answer: acetone molecule ( CH₃-CO-CH₃)
Explanation:
1) Acetone is CH₃-CO-CH₃
2) That is a molecule (build up of covalent bonds).
3) When dissolved, covalent bonded compounds remain as separate molecules, then it is said that the major species present in the solution is the molecule. The molecules of acetone are surrounded (sovated) by the molecules of water.
This as opposed to the case of ionic compounds that ionize. When a compound as NaCl dissolves in water, it ionizes completely, so the major speceies are not NaCl formulas, but the ions Na⁺ and Cl⁻, not molecules.
That leads to the answer: the major species present when acetone is dissolved in water is the molecules of acetone (you do not need to state the fact that the molecules of water are part of the solution, because that is not the target of the question).
