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3 years ago

Please help me, please

Chemistry

1 answer:

kumpel [21]3 years ago

6 0

The temperature of a substance is related to the speed of the substance's particles. So, when the temperature of a substance changes,the speed of the particles also changes. So B.

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Which one of the following represents an acceptable set of quantum numbers for an electron in an atom? (arranged as n, 1, m, and

babymother [125]

Answer:

The correct option is A) 3, 2, -2, -1/2.

Explanation:

Quantum numbers represent different properties regarding the level, sublevel and orbital in which an electron is. There are 4 quantum numbers:

Principal quantum number (n): indicates the level of energy and gives information about the size of an orbital. It can only take positive and integer values, e. g., 1, 2, 3...
Angular quantum number (l): indicates the sublevel of energy and provides information about the shape of the orbital. Some common shapes are spherical (l=0) and polar(l=1). Shapes for bigger l are more complicated. l values depend on n values. l values can be integers up to (n-1). For example. if n = 2, l can take the values 0 and 1.
Magnetic quantum number (m): it gives information about the orientation in space of an orbital. It may take any integer value between -l and +l. For example, if l = 1, m can take values -1, 0 and 1, each one referring to an orbital p along a different axis in the space (x, y and z axes).
Spin quantum number (ms): it refers to the spin angular momentum of an electron and it can take 2 values: -1/2 or +1/2.

A) 3, 2, -2, -1/2 is correct because it follows every rule.

B) 3, 3,-4, 1/2 is wrong because if n=3, l can only be up to 2, and l from -3 to +3.

C) 3,2,0,0 is wrong because ms cannot take the value 0.

D) 3,3,3, -1/2 is wrong because if n=3, l can only be up to 2.

E) 3, 4, 6, -1/2 is wrong because if n=3, l can only be up to 2, and l from -3 to +3.

4 0

3 years ago

What is the average yearly rate of change of carbon-14 during the first 5000 years?

erica [24]

Answer:

The average yearly rate of change of carbon-14 during the first 5000 years = 0.0004538 grams per year

Explanation:

Given that the mass of the carbon 14 at the start = 5 gram

At the end of 5,000 years we will have;

$A = A_0 \times e^{-\lambda \times t}$

Where

A = The amount of carbon 14 left

A₀ = The starting amount of carbon 14

e = Constant = 2.71828

$T_{1/2}$ = The half life

$\lambda = 0.693/T_{1/2}$

t = The time elapsed = 5000 years

λ = 0.693/ $T_{1/2}$ = 0.693/5730 = 0.0001209424

Therefore;

A = 5 × e^(-0.0001209424×5000) = 2.7312 grams

Therefore, the amount of carbon 14 decayed in the 5000 years is the difference in mass between the starting amount and the amount left

The amount of carbon 14 decayed = 5 - 2.7312 = 2.2688 grams

The average yearly rate of change of carbon-14 during the first 5000 years is therefore;

2.2688 grams/(5000 years) = 0.0004538 grams per year

The average yearly rate of change of carbon-14 during the first 5000 years = 0.0004538 grams per year.

5 0

3 years ago

How many moles of oxygen are in 25.45 g of caco3?

emmainna [20.7K]

From the periodic table:
mass of oxygen = 16 grams
mass of calcium = 40 grams
mass of carbon = 12 grams
mass of CaCO3 = 40 + 12 + 3(16) = 100 grams
Therefore, each 100 grams of CaCO3 contains 3 moles of oxygen
To know the number of oxygen moles in 25.45 grams, we will simply do cross multiplication as follows:
number of oxygen moles = (25.45 x 3) / 100 = 0.7636

3 0

3 years ago

How many mL of a .132 M aqueous solution of sodium chloride, NaCl, must be taken to obtain 3.59 grams of the salt?

Sever21 [200]

Answer:

465mL

Explanation:

Volume of a solution, V =Mass of substance, m/(Molarity of the solution of the substance, M × molar mass of the substance, M.m)

Given in the question,

M=.132M

M.m=23+35.5 = 58.5g/mol

m=3.59g

V= 3.59/(.132×58.5)

V = 0.465L

Volume in mL = volume in L × 1000

= 0.465 × 1000 = 465mL

Therefore, 465mL of a .132M aqueous solution of sodium chloride, NaCl, must be taken to obtain 3.59 grams of the salt

4 0

3 years ago

How many liters of water would it require to 36 grams of the substance?

Bas_tet [7]

3 liters

________________

3 0

2 years ago

Read 2 more answers