A student weighs out 0. 0422 g of magnesium metal. The magnesium metal is reacted with excess hydrochloric acid to produce hydrogen gas. A sample of hydrogen gas is collected over water in a eudiometer at 32. 0°c. The volume of collected gas is 43. 9 ml and the atmospheric pressure is 832 mmhg. Using the experimentally collected data, calculate r and the percent error.

Half-life is the time taken for the concentration of the substance to reduce by 50%. The original sample of strontium had a mass of 1.6 gms. Thus, option d is correct.

The half-life of any radioactive substance is the time period at which the concentration will get reduced to half the initial amount. The initial mass of Sr-90 is calculated as,

[tex]N(t) = N_{0} (\dfrac{1}{2})^{ \frac{t }{t 1/2}}[/tex]

Given,

Quantity of the remaining substance N (t) = 0.40 gm

Initial radioactive substance quantity [tex]N_{0}[/tex] =?

Time duration (t) = 56 years

Half-life = 28 years

Substituting values above:

[tex]\begin{aligned} 0.40 &= N_{0} (\dfrac{1}{2}) ^{{\frac{56}{28}}\\\\0.40 &= N_{0} (\dfrac{1}{2})^{2}\end{aligned}[/tex]

= 1.6 gm

Therefore, option d. the initial mass of Sr is 1.6 gm.

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The molarity of a solution in which 55. 49 g of calcium chloride is dissolved in enough water to make 500. ml of solution is 1M.

It is defined as number of moles of solute divided by volume of solution.

Given,

Mass of CaCl2 =55.49g

Molar mass of CaCl2 =40+35+35=110g

Mole= given mass/ molar mass

= 55.49/110=0.50mol.

Now, putting all values we get the molarity

Molarity =0.5×1000/500=1M

Thus, the molarity of given solution is 1M.

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Answer:

2 NaI ---> 2 Na + I₂

Explanation:

The only way the reactant NaI can decompose is by separating into 2 atoms, Na and I. However, you must take into account that iodine (I) exists as a diatomic molecule.

An equation is balanced when there is an equal amount of each element on both sides of the reaction. These amounts can be modified by adding coefficients in from of the molecules/atoms.

The unbalanced equation:

NaI -----> Na + I₂

Reactants: 1 sodium, 1 iodine

Products: 1 sodium, 2 iodine

The balanced equation:

2 NaI ---> 2 Na + I₂

Reactants: 2 sodium, 2 iodine

Products: 2 sodium, 2 iodine

The mass of CH₄ that is consumed is 10.598 g.

The enthalpy of a system is defined as the sum of the internal energy of a system and the energy that is produced due to its pressure and volume.

It is given by

H = U+PV

The following reaction takes place during the combustion of CH₄

[tex]CH_4(g)+2O_2(g)\rightarrow CO_2(g)+2H_2O(g)[/tex]

Energy evolved during the combustion, E = 587.9 kJ

Enthalpy of combustion of methane, ∆H = 890.3 kJ

[tex]No of moles of CH_4 =\frac{energy evolved}{enthalpy of combustion}[/tex]

= 587.9 /890

Mass of CH₄  that is consumed = no of moles × molar mass of CH₄

  = 587.9 /890 × 16

   = 10.598 g

The mass of CH₄  which is consumed is 10.598 g

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Answer:

Thiols contain stronger acids than alcohols

Explanation:

Answer:

Sulfur is a bigger atom than oxygen and has a lower electgronegativity value. Therefore, the lone pair availability in thiol is higher than alcohol

Explanation:

The piece of plastic has   1.256× 10¹³  protons  more than  that of electrons.

A proton is a subatomic particle with a defined mass of 1 and a charge of +1 (positive charge). The symbol for the proton is either p or p+.

An electron is a subatomic particle that has a negative electric charge and that actively orbits the nucleus of the atom .

To calculate ,

given ,

magnitude of charge , q=+2μC=+2×10⁻⁶

Since, protons carry positive charge. Then, we know that standard number of proton in 1 Coulomb of charge is,

1C=6.28×10¹⁸ protons

Number of protons in 1 microcoulomb charge is,

=6.28×10¹⁸×10⁻⁶

=6.28×10¹²

Then for the net charge of q, the number of protons is given as,

np= q×6.28×10¹²

np= 2×6.28×10¹²

np=1.256×10¹³ protons

Thus, the piece of plastic has 1.256×10¹³   more protons than electrons.

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Answer:

5.12 atm

Explanation:

Before you can use the Ideal Gas Law to find the pressure, you need to convert grams to moles (via molar mass).

Molar Mass (H₂): 2(1.008 g/mol)

Molar Mass (H₂): 2.016 g/mol

 1.8 grams H₂               1 mole
----------------------  x  ----------------------  =  0.893 moles H₂
                                 2.016 grams

The Ideal Gas Law equation looks like this:

PV = nRT

In this equation,

-----> P = pressure (atm)

-----> V = volume (L)

-----> n = moles

-----> R = Ideal Gas Constant (0.0821 L*atm/mol*K)

-----> T = temperature (K)

After converting Celsius to Kelvin, you can plug the given values into the equation and simplify to find the pressure.

P = ? atm                                R = 0.0821 L*atm/mol*K

V = 4.3 L                                T = 27 °C + 273.15 = 300.15 K

n = 0.893 moles

PV = nRT

P(4.3 L) = (0.893 moles)(0.0821 L*atm/mol*K)(300.15 K)

P(4.3 L) = 22.0021

P = 5.12 atm

**Based on my past experiences, I believe the constant (R) you provided may have been mistyped. Instead of 0.821, I used 0.0821.**

The only way increase the buffer capacity is to increase the total concentration of the system (conjugated acid + base).

The buffer capacity can be defined as the amount of strong base needed to change the pH of 1 liter of solution by 1 pH unit.

To increase buffer capacity to modify buffer solution-

The buffer capacity of a buffer, consisting of a weak acid and its conjugated base is given by the following equation:

π=㏑ 10 [{H⁺} + K ÷ H⁺ + CKα [H⁺]  ÷ [H⁺]  + Kα]

With [H^+] the concentration of the H^+ ion ; C the total buffer concentration (i.e. acid + conjugated base) and Kα the acidity constant.

It is clear from this equation that the buffer capacity is directly proportional to the concentration.

So the only way increase the buffer capacity is to increase the total concentration of the system (conjugated acid + base).

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The metabolic process that takes place in an organism's cells is called cellular respiration. Both photosynthesis and cellular respiration contribute carbon dioxide to the biogeochemical cycle.

What is biogeochemical cycle?

The mechanism that distributes and circulates abiotic chemical elements among the various realms of the planet is known as the biogeochemical cycle. The carbon, water, nitrogen, phosphorus cycle, etc. are all included.

Carbon dioxide is released during cellular respiration as a waste gas into the atmosphere, where it is then taken by plants to produce energy, which is then utilized by the organism, which then releases more carbon dioxide. The ecological chain's carbon cycle continues from the producer to the consumer.

Therefore, the carbon cycle is influenced by photosynthesis and cellular respiration.

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Ester is the major product formed in the reaction involving an acid anhydride dissolved in alcohol.

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The properties of all metals are "good conductors of heat and electricity".

Metals are excellent heat or electricity conductors and were malleable, ductile materials that may be pulled into wire and pounded into sheets. Apart from mercury, which appears a liquid at ambient temperature, most metals have solids with a distinctive silvery shine.

Due to the metals' atoms' ability to create a matrix across which outside electrons could easily travel, metals make good electrical and thermal conductors. The positive nuclei of the connecting metal ions are surrounded by a sea of electrons rather than orbiting their individual atoms.

Therefore, the properties of all metals are "good conductors of heat and electricity".

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The equilibrium constant, Keq for the reaction, given the data from the question is 0.084

The equilibrium constant, Keq for a reaction is the ratio of the concentration of the products raised to their coefficients to the ratio of the concentration of the reactants raised to their coefficients. For example, the equilibrium constant for the reaction nA + mB <=> eC can be obtained as follow

Keq = [C]^e / [A]^n × [B]^m

The equilibrium constant, Keq for the above reaction can be obtained as illustrated below:

Keq = [SO₂]^2 × [O₂] / [SO₃]^2

Keq = (0.17)^2 × (0.701) / (0.491)^2

Keq = 0.084

Thus, the equilibrium constant, Keq for the reaction is 0.084

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When an allergen binds with IgE antibodies on mast cells, resulting in release of chemical mediators, this reaction is called Type I reactions.

The Type I reactions is also known as immediate hypersensitivity reaction.

This reaction involve immunoglobulin E ( IgE ) - mediated release of histamine and other mediators from mast cells and basophils .

Examples : anaphylaxis and allergic rhinoconjunctivitis.

The IgE molecules bind to high - affinity receptors on the surface of mast cells and basophils and the subsequently cross-linking of these molecules with the allergen releases performed and newly synthesized mediators.

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The significant figures will be 1.

As, weight of acetylsalicylic acid = 0. 4 g

We obtain 400 mg when we convert 0.4g of acetylsalicylic acid to mg.

So, 400 milligrams are worth 0.4 grams when converted to grams.

There is just one significant figure because 0 before a decimal is not significant i.e. 4.

The digits of a number that have relevance in relation to the measurement's resolution are known as significant figures. Additionally known as significant figures in chemistry. All experimental measurements are subject to some degree of uncertainity.

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As a result, the dry gas volume at STP is 45.58 cm 3.

Water vapor is present in the gas. Since H2 is created during the reaction and water vapor is irrelevant when determining the equivalent weight, we only need the dry gas. As a result, the volume of H2 gas can be calculated using the ideal gas law.

P 1 = 750 mm Hg, 14 mm Hg, 736 mm Hg V = 50 cm 3 T = 17 0 C = 290 K

P = 760mmHg, V =?cm3, T = 0 0 and C = 273K.

The Gas equation follows.

P 1V 1/ T1 = P 2V 2/ T2

290/73650 = 273/760V 2

= 290760V 2

= 7365027V 2 = 45.58 cm

As a result, the dry gas volume at STP is 45.58 cm 3.

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When mixture of H2PO4- and OH- is allowed to react. The products of the reaction are as follow

H2PO4+ OH--------HPO4(2-)+H2O

In the reaction above H2PO4(2-) is donating the proton to OH Resulting in H2O and the deprotonated species. This makes it a bronsted lowry acid.

According to Bronsted lowry, acid are those which donate proton.

In the given problem, H2PO4- is bronsted lowry acid. So it donate electron to OH- to form water.

Thus, the product formed in the given reaction is water and H2PO4(2-).

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(a) The temperature goes up by 3⁰C.

(b) There is increase in temperature, so the reaction is exothermic.

(c) Examples of exothermic reaction include, rusting of Iron, burning of coal, reaction of strong acid and water.

(d) Examples of endothermic reaction include, melting solid salts and evaporating liquid water.

Exothermic reaction is a type of chemical reaction in which energy is transferred to or from the surroundings.

Examples of exothermic reactions include the following;

Endothermic reaction is a type of chemical reaction in which energy is absorbed from the surroundings.

Examples of endothermic reactions include the following;

From the increase in temperature from 15⁰C to 23⁰C, we can conclude that the temperature goes up by 3⁰C.

20⁰C - 17⁰C = 23⁰ - 20⁰C = 3⁰C.

Since there is increase in temperature, the reaction is exothermic.

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We do not perform the titration while the sample is at its original temperature because reaction is too slow at original temperature and requires high activation energy.

A titration is a method where the concentration of an unknown solution is ascertained by comparing it to a solution of known concentration. The analyte (the unknown solution) is typically added in a known amount to the titrant (the known solution) from a buret until the reaction is finished.

The slow energy step in the reaction process may require a high activation energy, and the proportion of activated molecules needed to reach this reaction at room temperature or original temperature is too low, so most molecules cannot cross this peak. As a result, the reaction at room temperature proceeds very slowly (the final product is not reached). Heat can enhance the proportion of active molecules and catalyse a larger-scale reaction.

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The percentage yield of the  new production technique is 82.8%

Production is the procedure by which finished products are obtained form the raw materials. The production process involves the passing of raw materials through a certain procedure that involves the use of certain machines and equipment to give us the required products.

We are told in the question that there are three shifts;

Shift 1 produces 4562 grams

Shift 2 produces 5783 grams

Shift 3 produces 5247 grams

Average production from the three shifts = 4562 grams + 5783 grams +  5247 grams/3 = 5197 grams

The theoretical average yield is =  7000 grams + 7000 grams + 7000 grams/3 = 7000 grams

Now the percentage yield = actual yield/ theoretical yield * 100/1

percentage yield = 5197 grams/7000 grams * 100/1

percentage yield = 82.8%

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Concentration difficulties can be caused by medical, cognitive, or psychological problems or may be related to sleep disorders or medications, Psychological conditions

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There are  0.94 g mass of [tex]CaCO_{3}[/tex] is required to react completely with 25. 0 ml of 0. 750 m HCl .

Calculation ,

Mass of [tex]CaCO_{3}[/tex] = ?

The 1000ml of HCl  = 27.375 g

then the 1 ml of solution contains HCl = 27.375 g/1000×1

25 ml  of solution contains HCl = 27.375 g/1000 × 25 = 0.684 g

The chemical equation can be given as :

[tex]CaCO_{3} +HCl[/tex]  → [tex]CaCl_{2} +CO_{2} +H_{2} O[/tex]

2 mol of HCl reacts with 1 mol of [tex]CaCO_{3}[/tex]

The amount of [tex]CaCO_{3}[/tex] reacted is given by ,

100/71 × 0.684 g = 0.9639 g = 0.94 g

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Answer:

Explanation:

The final answer has a different set of units. In particular, kilograms (kg) changes to grams (g) and meters (m) changes to centimeters (cm). To make this change, you need to multiply the first value by proportions.

When writing these proportions, it is important that they are arranged in a way that allows for the cancellation of units. For instance, since both kg and m are located in the numerator, they must be located in the denominators of the conversions.

Proportions:

1 kg = 1,000 g

1 m = 100 cm

The full expression:

As you can see, the old units cancel out and you are left with g and cm in the numerator.

Ethylene glycol has a specific heat of 0. 578 cal/(g°c). If 23.2 g of ethylene glycol absorbs 75.6 cal of heat energy. The temperature increase be 5.64°C.

The amount of heat needed to raise the temperature of 1 kg of substance.

It is expressed as

Q = mcΔT

where,

Q = Heat energy

m = Mass

c = Specific heat capacity

ΔT = Change in temperature.

Here,

Q = 75.6 cal

m = 23.3 g

c = 578  cal/(g°c)

Now put the values in above formula we get

Q = mcΔT

75.6 cal = 23.2 g ×  578  cal/(g°c) × ΔT

ΔT = 5.64°C

Thus from the above conclusion we can say that Ethylene glycol has a specific heat of 0. 578 cal/(g°c). If 23.2 g of ethylene glycol absorbs 75.6 cal of heat energy. The temperature increase be 5.64°C.

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Organometallic Chemical reaction is a Grignard reaction. The critical intermediate (which can be isolated and enables the final product) is the formation of a carbon bond.

The Grignard Reaction is an organometallic chemical reaction that mostly produces C-C bonds. When organic molecules are combined with the Grignard reagent, the Grignard reaction occurs (Rmgx).

The Grignard Reaction is the conversion of an aldehyde or ketone into secondary or tertiary alcohol by the addition of an organomagnesium halide (Grignard reagent). A primary alcohol is produced when formaldehyde and oxygen react.

Alcohol and water molecules have acidic hydrogen atoms that Grignard reagents quickly react with. A proton substitutes the halogen in a Grignard reaction with water, producing an alkane as the end result. Therefore, the Grignard reagent offers a two-step process for changing a haloalkane into an alkane.

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The pH of a 0.50 M solution of base B is found to be 10.19. The Kb of the base is 4.8 × 10⁻⁸.

Let's consider the following basic reaction.

B(aq) + H2O(l) ⇄ BH(aq) + OH⁻(aq)

First, we will calculate the pOH of the solution using the following expression. (14-10.19)=3.81

antilog -3.81=1.55×10^-4/0.50=4.8×10^-8

The pH of a 0.50 M solution of base B is found to be 10.19. The Kb of the base is 4.8 × 10⁻⁸.

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The [tex]K_b[/tex] of the base b is 4.805 × 10⁻⁸.

The dissociation constant is a type of equilibrium constant that measures the degree of dissociation of a salt.

[tex]K_a[/tex] is the dissociation constant for the acid which describes the strength of an acid.

[tex]K_b[/tex] is the dissociation constant of the base which describes the strength of a base.

pOH = 14 - pH = 14 - 10.19 = 3.81

pOH = -log[OH⁻]

3.81 = -log[OH⁻]

Antilog (-3.81) = [OH⁻]

[OH⁻] = 1.55 × 10⁻⁴

Here,

[tex]K_b= \frac{[BH^+][OH^-]}{[B]}[/tex]

     = [tex]\frac{(1.55\times10^{-4})(1.55\times10^{-4})}{0.50}[/tex]

     = 4.805 × 10⁻⁸

The Kb of the base b is 4.805 × 10⁻⁸

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Acidosis is a disorder in which there is excess acid in the body. This condition can lead to hyperkalemia due to the diffusion of hydrogen ions in the intracellular fluid.

Hyperkalemia is an increased concentration of the fluid potassium level than normal. Though potassium (K) is needed by the body for various functions of the nervous system and muscles their excess can lead to diseases.

It can also be caused by acidosis, where the concentration of the hydrogen ion increases in the intracellular fluid which leads to a large movement of potassium ions toward the extracellular fluid.

Therefore, the condition of acidosis can cause hyperkalemia.

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Answer:

The longest continuous chain

Explanation:

As the temperature increases, the speed of gas molecules increases

The kinetic theory state about the relationship between the speed and temperature of gas molecules as with an increase in temperature, the speed of gas molecules increases.

The energy that an object possesses as a result of its motion is known as kinetic energy.

The average of the kinetic energies of all the particles in a system is known as the average kinetic energy.

The following equation provides the answer:

K = [tex]\frac{3RT}{2}[/tex]

K= kinetic energy

R= gas constant

T= temperature

The kinetic theory of matter states that all matter is made of small particles that are in random motion and that have space between them.

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