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3 years ago

Plz help me ppl I don't understand

Chemistry

2 answers:

labwork [276]3 years ago

7 0

The chart is about atomic structure: at the top, the left box is "nucleus" and the right is "electron cloud".

On the left, under nucleus, the two boxes are: "protons" on the right and "neutrons" on the left. Under proton is elements which is given and under neutrons, it is "isotopes".

On the right, under electron cloud, the next box is "electrons" and then the lower box is "ions".

Ganezh [65]3 years ago

4 0

The table shows the classical model of atoms.

An atom is made up of a dense nucleus (left) and electron cloud (right) whirling around the nucleus.

Within the nucleus, there are protons (left) and neutrons (middle). Within the electron cloud are the electrons (right most).

If the number of neutrons is different but the no. of protrons is the same, that is called isotope (left). If a neutral atom gains or loses, it becomes an ion (right).

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If 45.0 mL of ethanol (density =0.789g/mol) initially at 6.0°C mix with 45.0 mL of water (density =1.0 g/mol) initially at 28.0°

Likurg_2 [28]

The final temperature of the mixture : 21.1° C

<h3>Further explanation </h3>

The law of conservation of energy can be applied to heat changes, i.e. the heat received / absorbed is the same as the heat released

Q in(gained) = Q out(lost)

Heat can be calculated using the formula:

Q = mc∆T

Q = heat, J

m = mass, g

c = specific heat, joules / g ° C

∆T = temperature difference, ° C / K

Q ethanol=Q water

mass ethanol=

$\tt mass=\rho\times V\\\\mass=0.789\times 45=35.505~g$

mass water =

$\tt mass=1~g/ml\times 45~ml=45~g$

then the heat transfer :

$\tt 35.505\times 2.42~J/g^oC\times (t-6)=45\times 4.18~J/g^oC\times (28-t)\\\\85.922t-515.533=5266.8-188.1t\\\\274.022t=5782.33\rightarrow t=21.1^oC$

5 0

2 years ago

How many grams in 11.9 moles of sulfur? Avogadro’s number: 6.02x1023 atoms = 1 mole Molar mass of sulfur: 32.06 g sulfur = 1 mol

sergiy2304 [10]

Answer:

Mass = 0.37 g

Explanation:

Given data:

Number of moles of sulfur = 11.9 mol

Mass of sulfur in 11.9 mol = ?

Molar mass of sulfur = 32.06 g

Solution:

Number of moles = mass/molar mass

by putting values,

11.9 mol = mass/ 32.06 g/mol

Mass = 11.9 mol × 32.06 g/mol

Mass = 0.37 g

4 0

2 years ago

The solubility of o2 at 20c is 1.38 x10^-3. the partial presure of o2 in the air at sea level is 0.27 atm. using henery;s law, c

netineya [11]

<u>Answer:</u> The solubility of oxygen at 682 torr is $4.58\times 10^{-3}M$

<u>Explanation:</u>

To calculate the molar solubility, we use the equation given by Henry's law, which is:

$C_{A}=K_H\times p_{A}$

Or,

$\frac{C_{1}}{C_{2}}=\frac{p_{1}}{p_2}$

where,

$C_1\text{ and }p_1$ are the initial concentration and partial pressure of oxygen gas

$C_2\text{ and }p_2$ are the final concentration and partial pressure of oxygen gas

We are given:

Conversion factor used: 1 atm = 760 torr

$C_1=1.38\times 10^{-3}M\\p_1=0.27atm\\C_2=?\\p_2=682torr=0.897atm$

Putting values in above equation, we get:

$\frac{1.38\times 10^{-3}}{C_2}=\frac{0.27atm}{0.897atm}\\\\C_2=\frac{1.38\times 10^{-3}\times 0.897atm}{0.27atm}=4.58\times 10^{-3}M$

Hence, the solubility of oxygen gas at 628 torr is $4.58\times 10^{-3}M$

4 0

2 years ago

The definition of the acceleration states that an object accelerates when it

maks197457 [2]

Answer: Acceleration and velocity

Explanation:

Newton's second law says that when a constant force acts on a massive body, it causes it to accelerate, i.e., to change its velocity, at a constant rate. In the simplest case, a force applied to an object at rest causes it to accelerate in the direction of the force.

5 0

1 year ago

Read 2 more answers

Which of the following is not included in John Dalton's modern theory of the atom?

Akimi4 [234]

The answer for the following question is option "C".

Option C is not included in the John Dalton's modern theory of an atom.

"It states atoms of different elements combine to form new compound" but not new elements

Explanation:

According to John's Dalton's modern theory of an atom:

1. All matter is composed of atoms.

2. Atoms cannot be created,destroyed or subdivided in the ordinary chemical reactions.

3. Atoms of one element differ in the properties from atoms of an another element.

(i.e.)Each and every atom of the element has its own unique properties of their own.

4. Atoms of one element combine with the atoms of another element to <u>form new compound.</u>

5. Atoms that make up an element are identical to each other.

7 0

3 years ago