Answer:
Metals are good conductors of heat and electricity, and are malleable (they can be hammered into sheets) and ductile (they can be drawn into wire). Most of the metals are solids at room temperature, with a characteristic silvery shine (except for mercury, which is a liquid). Nonmetals are (usually) poor conductors of heat and electricity, and are not malleable or ductile; many of the elemental nonmetals are gases at room temperature, while others are liquids and others are solids.
Explanation:
Sodium is a silver-colored metal which is soft enough to cut with a knife. It is an extremely reactive metal, and is always found naturally in ionic compounds, not in its pure metallic form. Pure sodium metal reacts violently (and sometimes explosively) with water, producing sodium hydroxide, hydrogen gas, and heat:
Chlorine is a poisonous, yellow-green gas, with a very sharp odor, a
Chemical change happen cuz these 2 elements will combine to form a new compound which’s NaCl ( table salt )
Answer:
See Explanation
Explanation:
A decreasing temperature indicates that the dissolution process for the ammonium chloride requires input of energy from surroundings. That is, the process is essentially 2 parts => system (object of interest - NH₄Cl) and the surroundings (everything else - solvent - H₂O). The surroundings (water) solvent is showing a <u>measured</u> decrease in temperature or loss of energy (exothermic to surroundings) which flows into the system (NH₄Cl) and effects dissolution of salt into solution (endothermic to system).
Answer:
Explanation:
From the given information:
Camphor may be reduced as readily in the presence of sodium borohydride(NaHB4). The resulting compound which is stereoselective requires 1 mole of sodium borohydride (NaHB4) to reduce 1 mole of camphor in this reaction. The reaction is shown below.
Through the reduction process of camphor, the reducing agent can reach the carbonyl face with a one-carbon linkage. The product stereoisomer is known as borneol.
If the molecular weight of camphor = 152.24 g/mol
and it mass = 200 mg
The its no of moles = 200 mg/ 152.24 g/mol
= 1.3137 mmol
Now the amount of the required mmol for NaBH4 to be consumed in the reaction = 5.2 × 1.3137 mmol
= 6.831 mmol
since the molar mass of NaBH4 = 37.83 g/mol
Then, using the same formula:
No of moles = mass/molar mass
mass = No of moles × molar mass
mass = 6.831 mmol × 37.83 g/mol
mass of NaBH4 used = 258.42 mg
He realized that the physical and chemical properties of elements<span> were related to their atomic mass in a '</span>periodic<span>' way, and </span>arranged<span> them so that groups of </span>elements<span> with similar properties fell into vertical columns in </span>his table<span>.
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