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3 years ago

A lead atom has a mass of 3.14 x 10 to the negative 22nd g.How

Chemistry

1 answer:

frozen [14]3 years ago

4 0

Explanation:

The given data is as follows.

Mass of a lead atom = $3.14 \times 10^{-22}$

Volume = 2.00 $cm^{3}$

Density = 11.3 $g/cm^{3}$

As it is mentioned that 1 cubic centimeter contains 11.3 grams of lead.

So, in 2 cubic centimeter there will be $2 \times 11.3 g = 22.6 g$ of lead atoms.

One lead atom has a mass of $3.14 \times 10^{-22}$ . Therefore, number of atoms present in 22.6 g of lead will be as follows.

$\frac{22.6 g}{3.14 \times 10^{-22}}$

= $7.197 \times 10^{22} atoms$

Thus, we can conclude that there are $7.197 \times 10^{22} atoms$ of lead are present.

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Use the Bohr Model below to answer the questions:

Bas_tet [7]

Answer:

Ca(Calcium)

20 electrons

2 valence electrons

Explanation:

3 0

2 years ago

Sugar has a lower melting point than salt because sugar is made of _________.

il63 [147K]

The correct answer is Crystals.

Unlike sugar, salt is not made out of crystals, but both salt and sugar are made out of atoms, that is molecules, and can have ions.

4 0

3 years ago

What is the mass of a sample of metal that is heated from 58.8°C to 88.9°C with a

Vadim26 [7]

Answer:

$\boxed {\boxed {\sf 333 \ grams}}$

Explanation:

We are asked to find the mass of a sample of metal. We are given temperatures, specific heat, and joules of heat, so we will use the following formula.

$Q= mc \Delta T$

The heat added is 4500.0 Joules. The mass of the sample is unknown. The specific heat is 0.4494 Joules per gram degree Celsius. The difference in temperature is found by subtracting the initial temperature from the final temperature.

ΔT= final temperature - initial temperature

The sample was heated <em>from </em> 58.8 degrees Celsius to 88.9 degrees Celsius.

ΔT= 88.9 °C - 58.8 °C = 30.1 °C

Now we know three variables:

Q= 4500.0 J
c= 0.4494 J/g°C
ΔT = 30.1 °C

Substitute these values into the formula.

$4500.0 \ J = m (0.4494 \ J/g \textdegree C)(30.1 \textdegree C)$

Multiply on the right side of the equation. The units of degrees Celsius cancel.

$4500.0 \ J = m (13.52694 J/g)$

We are solving for the mass, so we must isolate the variable m. It is being multiplied by 13.52694 Joules per gram. The inverse operation of multiplication is division, so we divide both sides by 13.52694 J/g

$\frac {4500.0 \ J }{13.52694 J/g}= \frac{m (13.52694 J/g)}{13.52694 J/g}$

The units of Joules cancel.

$\frac {4500.0 \ J }{13.52694 J/g}= m$

$332.6694729 \ g =m$

The original measurements have 5,4, and 3 significant figures. Our answer must have the least number or 3. For the number we found, that is the ones place. The 6 in the tenth place tells us to round the 2 up to a 3.

$333 \ g \approx m$

The mass of the sample of metal is approximately <u>333 grams.</u>

8 0

2 years ago

What NaCl NaCl concentration results when 249 mL 249 mL of a 0.850 M 0.850 M NaCl NaCl solution is mixed with 667 mL 667 mL of a

tamaranim1 [39]

Answer:

The answer to your question is 0.54M

Explanation:

Data

Final concentration = ?

Concentration 1 = 0.850 M

Volume 1 = 249 ml = 0.249 l

Concentration 2 = 0.420 M

Volume 2 = 0.667 M

Process

1.- Calculate the number of moles in both solutions

Number of moles 1 = Molarity 1 x Volume 1

= 0.850 x 0.249

= 0.212

Number of moles 2 = Molarity 2 x Volume 2

= 0.420 x 0.667

= 0.280

Total number of moles = 0.212 + 0.280

= 0.492

2.-Calculate the final volume

Final volume = Volume 1 + Volume 2

Final volume = 0.249 + 0.667

= 0.916 l

3.- Calculate Molarity

Molarity = 0.492 / 0.916

Molarity = 0.54

4 0

3 years ago

Delta S will be positive for the reaction ________. a. 2Hg (l) + O2(g) ----------> 2HgO (s) b. 2NO2 (g) -------> N2O4(g) c

nordsb [41]

Answer:

BaF2(s) ------> Ba2 (aq) + 2F- (aq)

Explanation:

Entropy refers to the degree of disorderliness in a system. Processes that lead to greater disorderliness in a system are said to increase the entropy of the system or lead to a positive value of ΔS.

If we consider the process, BaF2(s) ------> Ba2 (aq) + 2F- (aq), we will notice that ions were produced in solution thereby increasing the disorderliness of the system.

8 0

3 years ago