URGENT

A 10 M concentrated stock solution of NaCl is used to prepare 3 liters of diluted 1 M solution. Which of the following is true for the process used to achieve the required dilution?

The volume of stock solution used is less than 0.2 liters.
The volume of stock solution used is less than 3 liters.
The volume of the solvent used is less than 0.2 liters.
The volume of the solvent used is more than 3 liters.

Answer:

0.429 M

Explanation:

To find the molarity, you need to (1) convert grams to moles (using the molar mass), then (2) convert mL to L, and then (3) calculate the molarity (using the molarity ratio).

(Step 1)

Molar Mass (NaCl): 22.990 g/mol + 35.453 g/mol

Molar Mass (NaCl): 58.443 g/mol

18.8 grams NaCl               1 mole
--------------------------  x  ------------------------  =  0.322 moles NaCl
                                     58.443 grams

(Step 2)

1,000 mL = L

 750.0 mL                1 L
------------------  x  -----------------  =  0.7500 L
                            1,000 mL

(Step 3)

Molarity (M) = moles / volume (L)

Molarity = 0.332 moles / 0.7500 L

Molarity = 0.429 M

The enthalpy change of the reaction is -44.79 kJ/mol.

We can define the enthalpy change as the energy that is given out or taken in in a reaction. it can be calculated from the enthalpies of formation of species by the use of the relation;

ΔH = ∑Enthalpy of formation of products -  ∑Enthalpy of formation of reactants

ΔHfC2H4(g) = +52kJ/mol

ΔHf H2O(g) = - 241.82 kJ/mol

ΔHf CH3CH2OH(g)= -234.61 kJ/mol

ΔHrxn  = (-234.61) - [52 + (- 241.82 )]

ΔHrxn  = (-234.61) - (-189.82)

ΔHrxn  = -44.79 kJ/mol

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Answer:

The volume of the gas sample at standard pressure is 819.5ml

Explanation:

Solution Given:

let volume be V and temperature be T and pressure be P.

[tex] V_1=250ml[/tex]

[tex] V_2=?[/tex]

[tex] P_{total}=735 mmhg[/tex]

1 torr= 1 mmhg

42.2 torr=42.2 mmhg

so,

[tex] P_{water}=42.2mmhg[/tex]

[tex] T_1=35°C=35+273=308 K[/tex]

Now

firstly we need to find the pressure due to gas along by subtracting the vapor pressure of water.

[tex] P_{gas}=P_{total}-P_{water} [/tex]

=735-42.2=692.8 mmhg

Now

By using combined gas law equation:

[tex]\frac{P_1*V_1}{T_1} =\frac{P_2*V_2}{T_2}[/tex]

[tex]V_2=\frac{P_1*}{P_2}*\frac{T_2}{T_1} *V_1[/tex]

[tex]V_2=\frac{P_gas}{P_2}*\frac{T_2}{T_1} *V_1[/tex]

Here [tex]P_2 \:and\: T_2[/tex] are standard pressure and temperature respectively.

we have

[tex]P_2=750mmhg \:and\: T_2=273K[/tex]

Substituting value, we get

[tex]V_2=\frac{692.8}{750}*\frac{273}{308} *250[/tex]

[tex]V_2= 819.51 ml[/tex]

Emphasis on object vs woman simply means s- e- x- ual objectification

This goes to say that it emphasizes seeing women as objects of se- xu- al pleasure

Objectification simply refers to the act of treating or viewing a person as an object, devoid of thought or feeling.

Most of the time, objectification is targeted at women and reduces them to objects of se- xu- al pleasure

So therefore, emphasis on object vs woman simply means se- xu- al objectification

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Answer:

Beryllium-9 is the isotope of beryllium with relative atomic mass 9.

Molality of C2H5OH is 1.1.27m.



What is Molality?

Molality is no.of moles present in One Kg solution .

Molality is represented by m

m= no.of moles/ weigt of solution in kg

Given is Molarity= 51.30M

molar mass of C2H5OH is 46g / mol , Density =0.9349g/ ml

Density=m/V

V = 107 ml

Molarity= no of moles/ Volume

51.5×46×107= x × 1000

weight of C2H5OH = 27.7g

molality = 27.7/1000××46

m= 1.27m

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Answer:

Sulfur

Explanation:

In general, elements are more reactive the more electronegative they are. The most electronegative elements are at the top-right of the periodic table. Since sulfur (S) is one unit up and one unit to the right of arsenic (As), it is considered more electronegative, and therefore more reactive, than arsenic.

The value 6.0 x 10^3- 2.3 × 10^3 in scientific notation is 3.7 × 10^3.

Scientific notation is a way to write very large or very small numbers so that they are easier to read and work with.

You express a number as the product of a number greater than or equal to 1 but less than 10 and an integral power of 10 .

There are two reasons to use scientific notation.

Given,

= 6.0 x 10^3- 2.3 × 10^3

= (6.0 - 2.3) × 10^3

= 3.7 × 10^3

Thus, we find that the value 6.0 x 10^3- 2.3 × 10^3 in scientific notation is 3.7 × 10^3.

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The three disadvantages of hard water are:

1. Hard water is unsuitable for washing because soap does not readily create a lather in it.

2. Soap may react and produce, wasting the soap.

3. Due to the development of calcium and magnesium carbonates, tea kettles will get furred.

Water that contains a lot of minerals is referred to as hard water. In limestone, chalk, or gypsum deposits, which are mostly composed of calcium and magnesium carbonates, bicarbonates, and sulphates, hard water is created as a result of percolation. A moderate health advantage from drinking hard water is possible. In industrial settings where water hardness is regulated to prevent expensive breakdowns in boilers, cooling towers, and other water-handling equipment, it can present serious issues. Hard water is frequently detected in home settings by the build-up of lime scale in kettles and water heaters as well as by the absence of foam when soap is agitated in water. Wherever there is a worry about water hardness, water softening is frequently employed to lessen the negative impacts of hard water.

write three disadvantages of hard water.​

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The best way to represent the concentration of a 1.75 M K2CrO4 solution is 1.75% K2CrO4 (option A).

Molarity is the concentration of a substance in solution, expressed as the number moles of solute per litre of solution.

The molarity is a measure of the concentration of a chemical species, in particular of a solute in a solution, in terms of amount of substance per unit volume of solution.

The molarity is measured in mol/L or M, hence, it can be said that the molarity of a solution is 0.1M.

However, the concentration of a solution is best represented by using %. In accordance with this question, the best way to represent the concentration of a 1.75 M K2CrO4 solution is 1.75% K2CrO4.

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The equilibrium constant of a reaction, [tex]K_{c}[/tex]  = 6.44 * 10⁵; option C.

Equilibrium constant, [tex]K_{c}[/tex] of a reaction is a measure of the ratio of the equilibrium concentration of the products of a reaction, to the equilibrium concentration of the reactants; with each concentration raised to the exponent corresponding to the coefficient in the balanced equation of the reaction.

[tex]K_{c} = \frac{(products)^{a}}{(reactants)^{b}}[/tex]

The balanced equation of the given reaction is as follows:

The concentrations at equilibrium of the species are as follows:

[NO] = 0.0542 M,

[O₂] = 0.127 M, and

[NO₂] = 15.5 M

Equilibrium constant, [tex]K_{c}[/tex] = (15.5)²/(0.127) * (0.0542)²

[tex]K_{c}[/tex]  = 6.44 * 10⁵

In conclusion, the equilibrium constant of a reaction, tells on in which direction, the reaction is favored at equilibrium.

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Answer:

1 x 10⁻¹¹ M

Explanation:

(Step 1)

Determine the pH.

pH = -log[H⁺]

pH = -log[1 x 10⁻³ M]

pH = 3

(Step 2)

Determine the pOH.

pH + pOH = 14

3 + pOH = 14

pOH = 11

(Step 3)

Determine the hydroxide (OH⁻) concentration.

[OH⁻] = 10^-pOH

[OH⁻] = 10⁻¹¹

[OH⁻] = 1 x 10⁻¹¹ M

Answer:

D. 1kg Aluminium

Explanation:

First of all, you have to know that you were given two quantities, volume and mass.

The relationship between both quantities is given by the formula of density which is:

Density = Mass / Volume

Volume = Mass / Density

Since mass is constant, it means that the volume is inversely proportional to the density.

Volume = k / Density where k is a constant.

This means that the substance with the lowest density would have the highest volume and the one with the highest density would have the highest lowest.

The density of the substances are given as:

Lead = 11.2

Iron = 7.874

Gold = 19.3

Aluminium = 2.7

This means that Aluminium would have the highest volume as its the least dense.

∆H for given reaction -847kJ

So

2 mol of Al releases 847KJ heat

4 mol Al releases

∆H=-1694KJ

It is given that the energy released during the reaction of 2 moles of Al metal is - 847 KJ. The n the heat energy released by 4 moles of Al will be - 1694 KJ.

The enthalpy change of a reaction is the heat energy absorbed or released by a reaction. For an endothermic reaction, the heat energy is absorbed and the enthalpy change is positive. For an exothermic reaction, where the energy is released, the enthalpy change will be negative.

The heat energy change during a reaction is equal to the product of mass, specific heat and temperature difference of the substanc eunder reaction or phase transition.

Given that, the heat evolved by 2 moles of Al is - 847 kJ. Then, the heat evolved when 4 moles of Al reacted is calculated as follows:

(4 × - 847) / 2 = - 1694 KJ.

Therefore, the heat energy released is  - 1694 KJ.

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Answer:

It's the button with the x, and a blank box above it.

Explanation:

Check the attachments, you'll see what it looks like. It will probably look different on your calculator, but the icon should be the same or similar.

The IUPAC name of this compound is diamminecarbonylchloroIridium ..

Isomers are structure of compund in different forms but they have same molecular mass .

The cis and trans form are given in the picture

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Answer:

23.55 L

Explanation:

USe the following 'identity' of gs laws

P1 V 1 / T1 = P2 V2 / T2         ( T must be in Kelvin)

re arrange to

P1 V 1  T2  /  (T1 P2)   = V2       NOW SUB IN THE VALUES

752 * 34.2 * ( 34 + 273.15) / [( 229 + 273.15) * 668]   = V2 = 23.55 L

Answer:

hydrogen bonding

Explanation:

I just think it is I am not sure

Answer: C. Dipole-dipole interactions.

Remember the fact

Randomness follows the order

#System A

As solid particles are dissolved in water their randomness increases so entropy increases

#System B

Gas is converted to liquid so entropy decreases as randomness decreases

Answer:

Refer to the attached page,

I've done the calculation over there

Answer:

75 kg or 75,000 g

Explanation:

Mass is a measurement that describes the amount of matter within an object. This is a constant measurement that does not change regardless of the object's location.

As such, a person's mass would be the same at both elevations.

**Their weight, however, may change.

** 1 kg = 1,000 g

Answer:

Explanation:

'nsofikldng[ousgafi'fjsngds[sbuofdia

Answer:

9.89 x 10²³ molecules H₂S

Explanation:

To find the molecules of H₂S, you need to (1) convert grams S to moles S (via the atomic mass of sulfur), then (2) convert moles S to moles H₂S (via the mole-to-mole ratio from equation coefficients), and then (3) convert moles H₂S to molecules H₂S (via Avogadro's Number). It is important to arrange the ratios/conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs to match the sig figs of the given value.

Atomic Mass (S): 32.065 g/mol

2 H₂S(s) + SO₂(g) -----> 3 S(s) + 2 H₂O(l)

Avogadro's Number:

6.022 x 10²³ molecules = 1 mole

79.0 g S           1 mole            2 moles H₂S          6.022 x 10²³ molecules
---------------  x  ---------------  x  ----------------------  x  -------------------------------------  =
                        32.065 g            3 moles S                          1 mole

=  9.89 x 10²³ molecules H₂S

Answer:

1.) 17.76 moles H₂O

2.) 323.1 g HCN

Explanation:

1.) An equation is balanced when there is an equal amount of each element on both sides of the reaction. The quantities can be modified by adding coefficients in front of the molecules.

The unbalanced equation:

Al₄C₃(s) + H₂O -----> Al(OH)₃(s) + CH₄(g)

Reactants: 4 aluminum, 3 carbon, 2 hydrogen, 1 oxygen

Products: 1 aluminum, 1 carbon, 7 hydrogen, 3 oxygen

The balanced equation:

Al₄C₃(s) + 12 H₂O -----> 4 Al(OH)₃(s) + 3 CH₄(g)

Reactants: 4 aluminum, 3 carbon, 24 hydrogen, 12 oxygen

Products: 4 aluminum, 3 carbon, 24 hydrogen, 12 oxygen

Now that the equation is balanced, you can use the relevant coefficients to construct a mole-to-mole ratio. This will allow you to convert between moles Al₄C₃ to moles H₂O.

 1.48 moles Al₄C₃           12 moles H₂O
----------------------------  x  ------------------------  =  17.76 moles H₂O
                                         1 mole Al₄C₃

2.) To find the mass of HCN, you need to (1) convert grams NH₃ to moles NH₃ (via molar mass), then (2) convert moles NH₃ to moles HCN (via mole-to-mole from equation coefficients), and then (3) convert moles HCN to grams HCN (via molar mass). It is important to arrange the coefficients in a way that allows for the cancellation of units.

Molar Mass (NH₃): 14.009 g/mol + 3(1.008 g/mol)

Molar Mass (NH₃): 17.033 g/mol

Molar Mass (HCN): 1.008 g/mol + 12.011 g/mol + 14.009 g/mol

Molar Mass (HCN): 27.028 g/mol

2 CH₄(g) + 3 O₂(g) + 2 NH₃(g)  ------> 2 HCN(g) + 6 H₂O(g)

203.6 g NH₃            1 mole            2 moles HCN           27.028 g
---------------------  x  ----------------  x  ------------------------  x  -----------------  =
                                17.033 g           2 moles NH₃             1 mole

=  323.1 g HCN

The element magnesium is often in fireworks because it burns with bright white light. It adds white sparks and hence, improves the overall brilliance of a firework.

The reaction is as follows:

                        [tex]2Mg (s) + O_2 (g) \rightarrow 2MgO(s) + energy[/tex]

The reaction is exothermic in nature.

                        [tex]Mg(s)+ 2H_2O \rightarrow Mg(OH)_2(s) + H_2 (g)[/tex]

                        [tex]Mg(s)+CO_2 \rightarrow 2MgO(s)+ C(s)[/tex]

As magnesium is highly flammable and burns with white bright light, hence it is used in fireworks to improve its overall experience.

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Answer:

2.56 moles

Explanation:

7.2 M is 7.2 moles/L

356 mL = .356 Liters

x moles / .356 Liters = 7.2 M (moles/L)

x = .356 * 7.2 = 2.5632 moles

Answer:

.900 J / g-C°

Explanation:

I assume you are looking for the specific heat of the metal

Specific heat =  J / g-C

                      = 6640 J / 348 g[ (43.6 - 22.4) ] = .900 J / g-C

The specific heat of the unknown metal is approximately [tex]\rm \( 0.90 \, \text{kJ/kg\°C} \)[/tex].

To find the specific heat of the unknown metal, we can use the formula:

[tex]\rm \[ q = m \cdot c \cdot \Delta T \][/tex]

where:

[tex]\rm \( q \)[/tex] = heat absorbed by the metal (in kJ)

[tex]\rm \( m \)[/tex] = mass of the metal (in g)

[tex]\rm \( c \)[/tex] = specific heat of the metal (in kJ/kg·°C)

[tex]\rm \( \Delta T \)[/tex] = change in temperature (in °C)

Given data:

[tex]\( m = 348 \, \text{g} \)\\\( \Delta T = 43.6°C \\\\- 22.4°C = 21.2°C \)\\\( q = 6.64 \, \text{kJ} \)[/tex]

Now, let's rearrange the formula to solve for [tex]\rm \( c \)[/tex]:

[tex]\rm \[ c = \frac{q}{m \cdot \Delta T} \][/tex]

Substitute the values:

[tex]\rm \[ c = \frac{6.64 \, \text{kJ}}{348 \, \text{g} \times 21.2°C} \][/tex]

Convert the mass to kg and temperature to °C:

[tex]\rm \[ c = \frac{6.64 \, \text{kJ}}{0.348 \, \text{kg} \times 21.2\°C} \]\\\\\ c \approx 0.90 \, \text{kJ/kg\°C} \][/tex]

The specific heat of the unknown metal is approximately [tex]\rm \( 0.90 \, \text{kJ/kg\°C} \)[/tex].

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Your question is incomplete, but most probably your full question was,

A piece of unknown metal weighs 348 g. When the metal piece absorbs 6.64 kJ of heat its temperature increases from 22.4°C to 43.6°C. Determine the specific heat of this metal. What is your unknown metal?

Answer:

15 is not a correct scientific measurement.

Explanation:

Is this helpful for You

Answer:

the answer is A

Explanation:

The weak ionization constant (Ka) for HNO₂ is:

[tex]\displaystyle K_a = \frac{[H^+][NO_2^-]}{HNO_2}[/tex]

Acid-ionization constant Ka can be described as a quantitative measure of the strength of an acid in solution. It can be represented as the equilibrium constant for a chemical reaction:

[tex]{\displaystyle {\ce {HA \longrightarrow A^- + H^+}}}[/tex]

The chemical species HA can dissociate into A⁻ the conjugate base of the acid and a hydrogen ion, H⁺. In equilibrium, when the concentrations will not change over time, because both forward and backward reactions have the same rate.

The ionization constant can be described as the ratio of products and reactants raised to stoichiometric powers.

The dissociation constant is defined as:

[tex]{\displaystyle K_{\text{a}}=\mathrm {\frac {[A^{-}][H^{+}]}{[HA]}} }[/tex]

Given the dissociation of the HNO₂ as follows:

HNO₂  ⇄  H⁺ + NO₂⁻

The weak ionization constant (Ka) for HNO₂  is equal to:

[tex]\displaystyle K_a = \frac{[H^+][NO_2^-]}{[HNO_2]}[/tex]

Therefore, option A is correct.

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Answer:

they're both completely different games

Explanation:

Answer: uh.. tricky

Explanation: