1. A) Calculate DO of water at 25 0 C, P 0 = 1.01x10 5 Pa; given: water vapor pressure (25 0 C) is 3.2x10 3 Pa and Henry constant of oxygen in water is 1.3x10 -8 mol/l.Pa b) How's DO content changed as increase or decrease water temperature? Explain.

Answer:

0.512 M

Explanation:

We'll begin by calculating the number of mole in 12 g of C₂H₆O₄. This can be obtained as shown below:

Mass of C₂H₆O₄ = 12 g

Molar mass of C₂H₆O₄ = (2×12) + (6×1) + (4×16)

= 24 + 6 + 64

= 94 g/mol

Mole of C₂H₆O₄ =?

Mole = mass /molar mass

Mole of C₂H₆O₄ = 12 / 94

Mole of C₂H₆O₄ = 0.128 mole

Next, we shall convert 250 mL to L. This can be obtained as follow:

1000 mL = 1 L

Therefore,

250 mL = 250 mL × 1 L / 1000 mL

250 mL = 0.25 L

Thus, 250 mL is equivalent to 0.25 L.

Finally, we shall determine the molarity of the solution. This can be obtained as follow:

Mole of C₂H₆O₄ = 0.128 mole

Volume = 0.25 L

Molarity =?

Molarity = mole /Volume

Molarity = 0.128 / 0.25

Molarity = 0.512 M

Thus, the molarity of the solution is 0.512 M

A magnesium ribbon is cleaned to remove the protective layer of basic magnesium carbonate from its surface, so that it may readily combine with the oxygen in air (on heating).

Answer:

Magnesium gets covered with a layer of magnesium oxide when kept in air for a long time. This layer hinders the burning of magnesium. Hence, it is to be cleaned before burning.

Answer: The correct option is C ( is very hard and burns cleanly).

Explanation:

COAL is a form of rock that is made up of mostly carbon amongst other elements which includes sulphur, nitrogen, hydrogen and oxygen. There are different types of coal which include:

--> anthracite ( 90% carbon)

--> bituminous coal ( 70-90% carbon)

--> lignite ( 60- 70% carbon) and

--> peat (60 % carbon).

Anthracite is the type of coal that contains the highest carbon content ( 90% carbon). This makes it very hard and is often a times referred to as HARD COAL. Anthracite is a higher quality coal for domestic and open fire heating. This is because it contains less impurities than other type of coal and thereby making it to BURN CLEANLY avoiding atmospheric pollution.

Answer:

pCH₄ = 0.540 atm

pC₂H₆ = 0.405 atm

pC₃H₈ = 0.505 atm

Explanation:

Step 1: Calculate the total number of gaseous moles

n = n(CH₄) + n(C₂H₆) + n(C₃H₈)

n = 0.320 mol + 0.240 mol + 0.300 mol = 0.860 mol

Step 2: Calculate the partial pressure of each gas

We will use the following expression.

pi = P × Χi

where,

pCH₄ = 1.45 atm × 0.320 mol/0.860 mol = 0.540 atm

pC₂H₆ = 1.45 atm × 0.240 mol/0.860 mol = 0.405 atm

pC₃H₈ = 1.45 atm × 0.300 mol/0.860 mol = 0.505 atm

Answer:

theory

Explanation:

if you assume something that you didn't see occuring it is called a theory

Answer:

c

Explanation:

Nh4OH + HCL ---> NH4Cl + H3O

so ph decreases as H3O increases

and OH also decreases

When NH4OH is added to a solution with HCI, the pH of the solution B ) increases as the OH- concentration increases.

NH₄OH is a strong base as a result of the presence of the OH compound which is a base as well. Bases have high pH and acids have low pH.

This means that as the OH- concentration increases, the solution is being made to be more basic which would lead to the pH rising.

In conclusion, option B is correct.

Find out more on Bases at https://brainly.com/question/15565260.

Answer:

bakit Kay's lahat Ng module mahirap

Answer:

39.02

Explanation:

From the question given above, the following data were obtained:

Isotope A:

Mass of A = 38

Abundance of A (A%) = 9.67%

Isotope B:

Mass of B = 39

Abundance of B (B%) = 78.68%

Isotope C:

Mass of C = 40

Abundance of C (C%) = 11.34%

Isotope D:

Mass of D = 41

Abundance of D (D%) = 0.31%

Average atomic mass of X =?

The average atomic mass of X can be obtained as follow:

Average = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100] + [(Mass of D × D%)/100]

= [(38 × 9.67)/100] + [(39 × 78.68)/100] + [(40 × 11.34)/100] + [(41 × 0.31)/100]

= 3.6746 + 30.6852 + 4.536 + 0.1271

= 30.02

Thus, the average atomic mass of X is 39.02

Answer:

huh what?

Explanation:

Is  196,96657  u

I hope I've helped :)

Answer:

kevin is right according to what i see

Answer:

mg2+ because it is a very good idea

Answer:

I'm pretty sure this is propanediol

Explanation:

I'm not sure how to explain it, but I believe this is the structure for propanediol. Please let me know if I misunderstood and don't hesitate to reach out with questions!

1,3-propan-diol is the chemical name the given structure: [tex]HOCH_2CH_2CH_2OH[/tex].

Chemical names are orderly systems for classifying and identifying various chemical compounds. They act as a benchmark for international scientific and research communication. For the development of many scientific domains, a standardised nomenclature system for chemicals must be created and adopted. Chemical names, which are made up of a combination of words and symbols, include detailed information on the make-up and structure of a certain substance. They frequently contain constituents, functional groups, and distinct modifiers that aid in describing the compound's varied attributes. 1,3-propan-diol is the chemical name the given structure: [tex]HOCH_2CH_2CH_2OH[/tex].

To know more about chemical name, here:

https://brainly.com/question/30633673

#SPJ6

The question is as follows: How many oxygen molecules are produced by the decomposition of 28.5 g of H2O2 (molecular mass = 34.0g / mol) according to the equation

2H2O2 (l) → 2H2O (l) + O2 (g)

Answer: There are [tex]2.52 \times 10^{23}[/tex] molecules are produced by the decomposition of 28.5 g of [tex]H_{2}O_{2}[/tex] according to the equation [tex]2H_{2}O(l) \rightarrow 2H_{2}O(l) + O_{2}(g)[/tex].

Explanation:

Given: Mass of [tex]H_{2}O_{2}[/tex] = 28.5 g

As moles is the mass of a substance divided by its molar mass. Hence, moles of [tex]H_{2}O_{2}[/tex] is calculated as follow.

[tex]Moles = \frac{mass}{molarmass}\\= \frac{28.5 g}{34.0 g/mol}\\= 0.838 mol[/tex]

According to the given equation, 2 moles of [tex]H_{2}O_{2}[/tex] gives 1 mole of [tex]O_{2}[/tex]. So, moles of [tex]O_{2}[/tex] produced by 0.838 moles of [tex]H_{2}O_{2}[/tex]  will be calculated as follows.

[tex]Moles of O_{2} = \frac{0.838 mol}{2}\\= 0.419 mol[/tex]

This means that moles of [tex]O_{2}[/tex] produced is 0.419 mol.

As per the mole concept, 1 mole of every substance has [tex]6.022 \times 10^{23}[/tex] molecules.

So, molecules of [tex]O_{2}[/tex] present in 0.419 mole are as follows.

[tex]0.419 \times 6.022 \times 10^{23}\\= 2.52 \times 10^{23}[/tex]

Thus, we can conclude that there are [tex]2.52 \times 10^{23}[/tex] molecules are produced by the decomposition of 28.5 g of [tex]H_{2}O_{2}[/tex] according to the equation [tex]2H_{2}O(l) \rightarrow 2H_{2}O(l) + O_{2}(g)[/tex].

Answer:

O 100

Explanation:

Answer: The statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.

Explanation:

A strong acid upon dissociation gives a weak conjugate base. This can also be said as stronger is the acid, weaker will be its conjugate base or vice-versa.

Hydrofluoric acid is a strong base as it dissociates completely when dissolved in water.

For example, [tex]HF \rightleftharpoons H^{+} + F^{-}[/tex]

The conjugate base is [tex]F^{-}[/tex] which is a weak base.

Acetic acid is a weak acid as it dissociates partially when dissolved in water. So, the conjugate base of acetic acid is a strong base.

[tex]CH_{3}COOH \rightarrow CH_{3}COO^{-} + H^{+}[/tex]

Thus, we can conclude that the statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.

Answer:

C thermal

Explanation:

Answer:

See explanation

Explanation:

A system is said to have attained dynamic equilibrium when the rate of forward reaction and the rate of reverse reaction are equal.

Considering the system under consideration;

I2(s)⇄I2(g)

Heating the container converts solid iodine to purple coloured iodine vapour.

At equilibrium, there will be no net change in the amount of solid iodine and iodine vapour present in the system because the two processes (forward and reverse reactions) occur at the same rate at equilibrium.

Answer:

all i can accurately say is that 2 and 4 are both true

Answer:

1: because phosphate contain oxide ions so that is base character

Answer:

80 m/s.

Explanation:

NOTE: This is a physics question. However, the solution to the question given below:

From the question given above, the following data were obtained:

Acceleration (a) = 2 m/s²

Initial velocity (u) = 20 m/s

Time (t) = 30 s

Final velocity (v) =?

The final velocity of the train can be obtained as shown below:

v = u + at

v = 20 + (2 × 30)

v = 20 + 60

v = 80 m/s

Therefore, the final velocity of train is 80 m/s.

Answer:

electron configuration

Explanation:

The arrangement of electrons in the atomic orbitals of an atom is called the electron configuration. Electron configurations can be determined using a periodic table.

Answer:

Molecular mass, M = 58.20 g/mol.

Explanation:

Given the following data;

Conversion:

760 mmHg = 1 atm

770 mmHg = 770/760 = 1.0131 atm

Temperature = 25°C = 273 + 25 = 298 K

To find the molecular mass, we would use the ideal gas law equation (density version);

PM = dRT

Where;

Making M the subject of formula, we have;

[tex] M = \frac {dRT}{P} [/tex]

Substituting into the formula, we have;

[tex] M = \frac {2.41 * 0.0821 * 298}{1.0131} [/tex]

[tex] M = \frac {58.9626}{1.0131} [/tex]

Molecular mass, M = 58.20 g/mol.

Answer:

Cr(NO3)3 (aq) +K3PO4 (s)

Explanation:

Answer:

Coriolis Effect

Explanation:

The Coriolis Effect is caused by Earths rotation. We can not only see this affecting how winds move, but also where storms form and the movement of  oceans currents.

Answer:

0.535 atm

Explanation:

Since the volume of the tank is constant, we use Gay- Lussac's law to find the pressure at 180°C.

So, P₁/T₁ = P₂/T₂ where P₁ = pressure at S.T.P = 1 atm, T₁ = temperature at S.T.P = 273.15 K, P₂ = pressure of gas at 180 °C and T₂ = 180 °C = 273.15 + 180 K = 453.15 K

So, P₁/T₁ = P₂/T₂

P₂ = P₁T₂/T₁

Substituting the values of the variables into the equation, we have

P₂ = P₁T₂/T₁

P₂ = 1 atm × 453.15 K/273.15 K

P₂ = 1 atm × 1.66

P₂ = 1.66 atm

We now need to find the total number of moles of each gas present

number of moles of nitrogen = mass of nitrogen, m/molar mass of nitrogen molecule M

n = m/M

m = 2.5 g and M = 2 × atomic mass of nitrogen (since it is diatomic) = 2 × 14 g/mol = 28 g/mol

So, n = 2.5 g/28 g/mol

n = 0.089 mol

number of moles of chlorine, n' = mass of chlorine, m'/molar mass of chlorine molecule M'

n' = m'/M'

m' = 13.3 g and M = 2 × atomic mass of chlorine (since it is diatomic) = 2 × 35.5 g/mol = 71 g/mol

So, n' = 13.3 g/71 g/mol

n' = 0.187 mol

So, the total number of moles of gas present is n" = n + n' = 0.089 mol + 0.187 mol = 0.276 mol

So, the partial pressure due to nitrogen gas, P = mole fraction of nitrogen × pressure of gas at 180 °C

P = n/n" × P₂

P = 0.089 mol/0.276 mol × 1.66 atm

P = 0.322 × 1.66 atm

P = 0.535 atm

Answer:

0.723 moles (5 s.f.)

Explanation:

Whenever there is a chemical equation, ensure that it is balanced. This is because a balanced chemical equation tells us the mole ratio (not the ratio of their masses), which means the relationship of the number of moles of reactants or products with one another.

The chemical equation given has already been balanced. Looking at the coefficients of HBr and Ba(OH)₂, the mole ratio of HBr to Ba(OH)₂ is 2: 1.

• 1 mole of Ba(OH)₂ is needed to react with 2 mole of HBr

Find the number of moles of HBr present:

Number of moles= mass ÷mr

Amount of HBr

= 117 ÷(1 +79.9)

= 1.4462 moles (5 s.f.)

Since the amount of Ba(OH)₂ required is half the amount of HBr present,

amount of Ba(OH)₂ required

= 1.4462 ÷2

= 0.723 moles (3 s.f.)

Notes:

• mr

= relative molecular mass

= sum of relative atomic masses (which can be found in the periodic table) in a molecule

Answer:

See explanation

Explanation:

In Bohr's theory, electrons are found in specific regions in space called orbits. These orbits are also called energy levels. An electron may move from one energy level to another by absorbing or emitting energy.

In the wave mechanical model, electrons are not found in a particular region in space according to Heisenberg's uncertainty principle.

We rather define a certain region in space where there is a high probability of locating the electron. This region in space where there is a high probability of locating the electron is called an orbital.

Hence, in the Bohr's model of the atom,electrons can surely be found in orbits while in the wave mechanical model, the orbital is a probability function that describes a region in space where an electron may be found.

Answer:

thnx for the points too muchee

Explanation:

Answer:

Explanation:

[tex]{hope it helps}}[/tex]