How many atoms of ^6Li are there in 12.3 g of ^6Li?

B, C

Explanation:

The Lewis dot structures that are valid are for B and C.

Regarding A;

The Lewis representation of carbon is correct. Each of the four dots symbolizes the four valence electrons.

However, the nitrogen with a single dot above, to the left, and below and a -3 charge isincorrect. For it to have a -3 charge, it must possess 8 Lewis dots (two on each side).

The nitrogen showing four dots (on top, right, bottom and left) is incorrect.

In B;

An oxygen having two dots positioned above and below with one dot on both sides is correct , as the 6 dots indicate oxygen's valence electrons.

In C;

A carbon shows two dots at each position and has a charge of +4. This is correct because the charge reflects that it has gained four electrons giving it 8 valence electrons.

In D;

An oxygen shows two dots above, to the left and below, with a charge of -2. This is incorrect as not all Lewis dots are present. Two are missing.

Answer:

The molar mass of the gas is 36.25 g/mol.

Explanation:

• To determine this, we utilize the mathematical relationship:

ν =

Where, ν represents the speed of light in a gas (ν = 449 m/s),

R denotes the universal gas constant (R = 8.314 J/mol.K),

T stands for the temperature of the gas in Kelvin (T = 20 °C + 273 = 293 K),

M is the molar mass of the gas in (Kg/mol).

ν =

(449 m/s) = √(3(8.314 J/mol.K)(293 K)/M,

by squaring both sides:

(449 m/s)² = (3(8.314 J/mol.K)(293 K))/M,

thus M = (3(8.314 J/mol.K)(293 K)/(449 m/s)² = 7308.006/201601 = 0.03625 Kg/mol.

Thus, the molar mass of the gas is 36.25 g/mol.

Answer:- 64015 J

Solution: The calorimeter contains 4250 mL of water, which is at a temperature of 22.55 degrees Celsius.

The water's density is 1 gram per mL.

Thus, the mass of water = = 4250 grams.

After introducing the hot copper bar, the final temperature of the water reaches 26.15 degrees Celsius.

Thus, for the water = 26.15 - 22.55 = 3.60 degrees Celsius.

The specific heat capacity of water is 4.184 .

To determine the heat absorbed by the water, we can use the following formula:

where q represents heat energy, m refers to mass, and c indicates specific heat.

Now let's substitute the values into the equation to perform the calculations:

q = 64015 J

Therefore, the water absorbs 64015 J of heat.