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3 years ago

Chemistry

1 answer:

grin007 [14]3 years ago

3 0

Answer:

Calcium

Explanation:

The symbol for the element with a mass number of 27 is actually Al for Aluminum instead of Co for Cobalt. Mass number refers to atomic mass, not atomic number.

Aluminum has an atomic mass of 26.982 or 27.

The letters to unscramble are I, M, C, Al, U, and C.

The mystery element is Calcium.

Hope that helps.

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How many atoms does the formula 2HgO have?

yKpoI14uk [10]

Answer:

Explanation:

2HgO

2 * 1 Hg atom = 2 Hg atoms

2 * 1 O atom = 2 O atoms

2+2 = 4 atoms total

3 0

3 years ago

2.70g of Zn (s) reacts with 50.0 mL of 1.00 M HCl solution to produce hydrogen gas according to the reaction. (R = 0.08206 L·atm

Anika [276]

Answer:

a. 0.0413 moles Zn

b. 0.0500 moles HCl

c. HCl is the limiting reactant

d. 0.0250 moles H₂

e. V = 0.56L

Explanation:

The reaction of Zn(s) with HCl is:

Zn(s) + 2HCl (aq) → ZnCl₂ (aq) + H₂(g)

Where 1 mole of Zn reacts with 2 moles of HCl.

a) To convert mass in grams to moles of a substance you need to use molar mass (Molar mass Zn: 65.38g/mol), thus:

2.70g Zn × (1mol / 65.38g) = 0.0413moles of Zn

b. Now, when you have a solution in molarity (Moles / L), you can know the moles of a volume of solution, thus:

Moles HCl:

50.0mL = 0.0500L × (1.00mol / L) = 0.0500 moles HCl

c. The limiting reactant is founded by using the chemical reaction as follows:

For a complete reaction of 0.0500 moles HCl you need:

0.0500 moles HCl × (1 mole Zn / 2 moles HCl) = 0.0250 moles Zn

As you have 0.0413 moles of Zn, and you need just 0.0250 moles for the complete reaction, Zn is the exces reactant and HCl is the limiting reactant

d.As HCl is limiting reactant and 2 moles of HCl react with 1 mole of H₂, moles of hydrogen formed are:

0.0500 moles HCl × (1 mole H₂ / 2 moles HCl) = 0.0250 moles H₂

e. Using PV = nRT, you can find volume of gas, thus:

PV = nRT

V = nRT / P

Where P is pressure 1atm at STP, n are moles, R is gas consant 0.08206Latm/molK and T is absolute temperature 273.15K at STP.

V = 0.0250molesₓ0.082atmL/molKₓ273.15K / 1atm

V = 0.56L

3 0

3 years ago

Give the structure corresponding to the name (s)−3−iodo−2−methylnonane.

Morgarella [4.7K]

The (s) in the chemical name of (s)-3-iodo-2-methylnonane indicates an S-configuration using the Cahn-Ingold-Prelog system of stereochemical nomenclature. The S-configuration means that an "imaginary" rotation from the highest priority substituent group to the lowest priority substituent group of the chiral center moves counterclockwise (to the left), provided that the lowest priority group is oriented "towards the back" (symbolized by dashed lines).

The highest priority group (iodine in this case) is the one with the highest atomic number and the lowest priority (hydrogen in this case) is one with the lowest atomic number.

If the atoms directly beside the chiral center have the same atomic number (Carbon-2 and Carbon-4 in this case), the atoms next to them will be evaluated until a point of difference is found. Carbon-2 is connected to 2 other carbon atoms and 1 hydrogen atom, while Carbon-4 is connected to only 1 carbon atom and 2 hydrogen atoms. Thus, Carbon-2 has a higher priority, with the point of difference being the carbon atom of the methyl group attached to Carbon-2. Both Carbon-2 and Carbon-4 are connected to one carbon atom from the main nonane chain, but the other atoms connected to Carbon-4 are hydrogen atoms only. Carbon-2 has an extra carbon connected to it and carbon has a higher atomic number than hydrogen.

If there is no point of difference, the central atom is not chiral and cannot be named using the Cahn-Ingold-Prelog system.

Thus, the structure of (s)-3-iodo-2-methylnonane is