How many grams of a 1000-gram radioactive sample are left after 3 half-lives? *
1 point
1000 grams
500 grams
250 grams
125 grams
2000 grams

The answer is D. Strong electrolytes

Strong electrolyte is a solute or solution that completely or almost  completely dissociates when in solution. These are good conductors of electricity only  when in molten/aqueous solution.

Strong electrolyte(aq) → Cation+(aq) + Anion−(aq)

The 'endpoint' in a titration refers to the measured volume of the titrant solution that results in a visible change, marking the completion of the reaction.

The 'endpoint' in a titration process refers to the measured volume of the titrant solution that causes a change in appearance, usually associated with a change in an indicator. A titrant, also known as a titrator, is a reagent of known concentration that is added from a burette to a solution of the analyte until the reaction is complete. This reaction completion, seen as a visible change, is the 'end point' of titration.

For Instance, in an acid-base titration, the endpoint is reached when the amounts of acid and base are stoichiometrically equal, and the pH of the solution suddenly changes. This process typically involves an indicator, such as phenolphthalein, that changes color at the endpoint.

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The 'end point' during a titration refers to the volume of the 'titrant' solution that leads to a noticeable color change in an indicator, signifying that the reaction has concluded.

In the process of a titration, the so-called 'end point' is the measured volume of the titrant solution (option B) that causes an observable change in appearance. This noticeable transformation usually takes the form of a change in an indicator. The end point of a titration is crucial as it signifies exactly when the reaction has reached completion.

For instance, let's consider a standard acid-base titration. In this case, the titrant (the solution in the burette) is gradually added to the analyte (the substance or solution being analyzed in the conical flask). An acid-base indicator, such as phenolphthalein, changes color to indicate the attainment of the end point, i.e., when stoichiometrically equivalent amounts of acid and base have reacted.

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Answer:

Data given

there are 120! because:

04 multiplied by 3 to make 12,

and since there are 10 units,

you multiply 12 by 10,

you get 120 oxygen atoms!

it is A. Because of a release of pressure from plate movement

  It’s A.  Because the tectonic plates move by the movements of the earths crust

Answer: 3- The average speed of the molecules would reduce.

It has been mentioned that the container in which the ideal gas is cooled from 50 degree Celsius to 25 degree Celsius has constant volume. Since the volume of the container is constant, the molecular mass would remain the same. Also since the volume is constant even though the gas is cooled down,the average distance between the molecules would remain the same.

Since the temperature is reduced from 50 degree Celsius to 25 degree Celsius, the movement and the kinetic energy associated with the gas molecules would reduce. Hence the average speed of the molecules would reduce.

Pyridinium will react with both OH- and HCO3-, whereas the ketones will only react with concentrated OH-, while Butan-2-one cannot react with either of above.

a) Butan-2-one: cannot react with both hydroxide ion and bicarbonate.

b) Pyridinium: can react with both hydroxide ion and bicarbonate.

c) ketones : can only react with concentrated OH-

Here we have to draw the electric field between two negatively charged particles and the effect of distance on it have to discuss.

The electric field between the two negatively charged particle are shown in the figure. There will be repulsion between the same charge particle. As the distance between the charged particle increases the force of repulsion will decreases.

The force of attraction between two charged particle was described by Coulomb, which is known as coulomb's inverse square law.

As per the law the force of attraction or repulsion between two charged particles is proportional to the multiplication of the charge and inversely proportional to the square of the distance between the particles.

Mathematically it can be represented as -

the force F ∞ q₁ × q₂ (q is the charge of the particles) and F ∞ [tex]\frac{1}{r^{2} }[/tex] (r is the distance between the two charge particles)

By combining F ∞ [tex]\frac{q_{1}q_{2}}  {r^{2}  }[/tex]

Or, F = ∈⁻¹  [tex]\frac{q_{1}q_{2}}  {r^{2}  }[/tex] (where ∈  = permittivity of the medium)

Thus as per the law as the distance (r) increases the force of repulsion between the two negatively charged particle will increase.

Thus the electric field between two negative charge particle is shown and  the effect of distance on it explained.

As the distance [tex](\text{r})[/tex] increases the force of repulsion between two charged particle will increase.

Explanation:

Given information:

The electric field line is drawn between two negatively charged particle.

Now, as we know

According to coulomb's law, the force of attraction or repulsion between two charged particle is proportional to the product of the charge and inversely proportional to the square of the distance between the particles.

As:

[tex]F = k. (q_1.q_2)\\F=k.(1/r^2)\\[/tex]

Where [tex]k[/tex] is the permittivity of the medium.

Now, according to the law as the distance increases the force of repulsion between two charged particle will increase.

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Hey there!:

a conjugate base  contains  one less  hydrogen atom and one more negative charge thant the acid  that formed  it . All acids have a conjugate base  , all base have a conjugate acid, acids  donate H⁺ when react.

Therefore:

H3PO4 -------------- H2PO4⁻

Hope that helps!

Answer;

55.86 moles

Explanation;

Six molecule of H2O is needed for every molecule of C6H12O6 to be produced.

This means the ratio of H2O: C6H12O6 is 6:1  

Let H2O mole= X  

Therefore...

X/9.31 = 6/1  

X= 6 x 9.31

X = 55.86 moles

55.86 moles of H2O are needed to produce 9.31 moles of C6H12O6.

The chemical formula for glucose (C6H12O6) indicates that there are 6 moles of water (H2O) needed for every mole of glucose produced. Therefore, to find out how many moles of water are needed for 9.31 moles of glucose (C6H12O6), you can multiply the number of moles of glucose by the ratio of moles of water to moles of glucose:

Number of moles of H2O = Number of moles of C6H12O6 × (6 moles of H2O / 1 mole of C6H12O6)

Number of moles of H2O = 9.31 moles × 6

Number of moles of H2O = 55.86 moles

So, 55.86 moles of H2O are needed to produce 9.31 moles of C6H12O6.

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The deeper the the water is the freasher/ cleaner it is

hey i'm late but if any of other readers need help on this question here it is Surface impurities easily reach the shallow water source.  ask me if you need any help why

Assuming that the source generates pitch at a constant frequency, the source is likely to be continuously moving away from Jamie the observer.

Doppler Shift describes the observation that relative movements between the source and receiver would alter the apparent wavelength of both acoustic and electromagnetic radiation.

Waves from a source moving towards an observer are compressed. A stationary observer would find the wavelength shorter and hence the frequency higher than they actually are at the source. Similarly, waves coming from a retreating source are stretched and experience an apparent decrease in frequency.

A low-pitch corresponds to a low vibration frequency and hence long wavelength. The observation that wavelength appears to be increasing corresponds to the scenario that sound waves are being stretched when there's an increase in the separation between the source and the observer.

The most appropriate for measuring the volume of water in a swimming pool is kilolitres.

Consider a pool that is 25 m long by 10 m wide with an average depth of 1.5 m.

V = lwh = 25 m × 10 m × 1.5 m = 375 m³

1 L = 1 dm³, so

V = 375 m³ × (10 dm/1 m)³ = 375 000 dm³ = 375 000 L = 375 kL

Thus, the cubic metre or kilolitre is more appropriate, because it gives more manageable numbers (i.e., between 0.1 and 1000)

Final answer:

The volume of water in a swimming pool is best measured in kiloliters due to the large amount of water pools hold, making it a more suitable and manageable unit than liters.

Explanation:

The most appropriate unit for measuring the volume of water in a swimming pool is kiloliters. When considering the size of a swimming pool and the large amount of water it holds, liters would be too small to effectively express this volume. Instead, using kiloliters, which represent thousands of liters, provides a more manageable and accurate measurement for such a substantial quantity of liquid.

It's important to select a unit that best corresponds with what is being measured. Since a swimming pool requires a significantly more substantial capacity for water compared to everyday containers, kiloliters are far more suitable than liters, which might be used for measuring smaller volumes, such as in a car's fuel tank. Hence, for the volume of a swimming pool, kiloliters are the ideal metric unit of capacity.

Answer: a) 1.97 grams of carbon disulfide will remain after 37.0 days.

              b) 2.85 grams of carbon monosulfide will be formed after 37.0 days.

Explanation: The decomposition of carbon disulfide is given as:

                          [tex]CS_2(g)\rightarrow CS(g)+S(g)[/tex]

at t=0                    4.83g             0          0

at t=37 days        4.83 - x            x           x

here,

x = amount of [tex]CS_2[/tex] utilised in the reaction

This reaction follows first order kinetics so the rate law equation is:

[tex]k=\frac{2.303}{t}log\frac{A_o}{A}[/tex]

where, k = rate constant

t = time

[tex]A_o[/tex] = Initial mass of reactant

A = Final mass of reactant

a) For this, the value of

[tex]k=2.80\times10^{-7}sec^{-1}[/tex]

t = 370 days = 3196800 sec

[tex]A_o[/tex] = 4.83

A = 4.83-x

Putting values in the above equation, we get

[tex]2.8\times 10^{-7}sec^{-1}=\frac{2.303}{3196800sec}log\left(\frac{4.83}{4.83-x}\right)[/tex]

x = 2.85g

Amount of [tex]CS_2 [/tex] remained after 37 days = 4.83 - x

                                                                     = 1.97g

b) Amount of carbon monosulfide formed will be equal to "x" only which we have calculated in the previous part.

Amount of carbon monosulfide formed = 2.85g

Barium Sulfate [tex]\text{BaSO}_4[/tex] is chemically stable and safe for human consumption.

Barium Sulfide [tex]\text{BaS}[/tex] is toxic and shall be handled with care.

Barium ions [tex]\text{Ba}^{2+}[/tex] ions can damage cell membranes and are thus toxic to the human body.

Barium ions in barium sulfate, however, are held tightly in ionic lattice and barely dissolve in water. Barium sulfate thus stay intact and give rise to no harmful [tex]\text{Ba}^{2+}[/tex] ions when orally ingested.

Barium sulfide can dissolve in water at significant quantities to produce barium [tex]\text{Ba}^{2+}[/tex] ions and sulfide [tex]\text{S}^{-2}[/tex] ions. Barium ions are toxic aforementioned whereas sulfide ions can undergo hydrolysis to produce hydrogen sulfide, a weak acid that evolves and behaves as a toxic gas.

[tex]\text{BaS} \; (s)\to\text{Ba}^{2+} \; (aq) + \text{S}^{2} \; (aq)\\\text{S}^{2-}\; (aq) + 2\; \text{H}_2\text{O} \; (l) \rightleftharpoons \text{H}_2\text{S} \; (g) + 2 \; \text{OH}^{-} \; (aq)[/tex]

Metal atoms form metallic solids whose properties stem from positively charged metal ions embedded in a sea of delocalized electrons. Nonmetal atoms typically form covalent network solids which are continuous networks of nonmetal atoms bonded by covalent bonds.

The type of crystalline solid formed from Metal atoms is called metallic solid. Metallic solids are formed when positively charged metal ions are embedded in a sea of delocalized electrons leading to strong metallic bonding and a regular packed structure. The properties of metallic solids such as heat and electrical conductivity malleability and ductility are due to this arrangement.

On the other hand the type of crystalline solid formed from Nonmetal atoms generally forms covalent network solids. These are formed when nonmetal atoms are bonded together through covalent bonds in a continuous network. Diamonds (carbon atoms) and quartz (silicon and oxygen atoms) are examples of covalent network solids.

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Final answer:

To find the volume of water displaced by 46kg of copper, mass is converted to grams and divided by copper's density, which results in 5155.16 mL of water displaced. Copper granules will sink in water as its density is higher than water's.

Explanation:

To determine the volume of water displaced by 46kg of copper granules, we first convert the mass of copper to grams (since the density is given in grams per cubic centimeter). We have:

46 kg of copper * 1000 g/kg = 46000 g of copper.

Now, we use the density of copper (8.92 g/cm3) to find the volume of copper, which is the same as the volume of water displaced:

Volume of copper = Mass of copper / Density of copper = 46000 g / 8.92 g/cm3 = 5155.16 cm3.

Since 1 cm3 is equivalent to 1 mL, 5155.16 cm3 would be 5155.16 mL of water displaced.

Regarding the second question, since the density of water is 1.00 g/mL, which is lower than that of copper, copper granules will sink in the water.

The balanced equation is MgCl₂ +2AgNO₃ ⟶ 2AgCl + Mg(NO₃)₂

Step 1. Start with the most complicated-looking formula [Mg(NO₃)₂].

Put a 1 in front of it and balance its atoms.

MgCl₂ +AgNO₃ ⟶ AgCl + 1Mg(NO₃)₂

Step 2. Balance Mg.

1MgCl₂ +AgNO₃ ⟶ AgCl + 1Mg(NO₃)₂

Already balanced —1 atom each side.

Step 3. Balance N.

We have 2 N on the right-hand side and 1 N on the left. We need 2 N on the left. Put a 2 in front of AgNO₃.

1MgCl₂ +2AgNO₃ ⟶ AgCl + 1Mg(NO₃)₂

Step 4: Balance O

Done. We have 6 O on the left and 6 O on the right.

Step 5. Balance Ag.

We have 2 Ag on the left, so we need 2 Ag on the right. Put a 2 in front of AgCl.

1MgCl₂ +2AgNO₃ ⟶ 2AgCl + 1Mg(NO₃)₂

The balanced equation is

MgCl₂ +2AgNO₃ ⟶ 2AgCl + Mg(NO₃)₂

Answer:

1,2,2,1

Explanation:

Mass number is the sum of protons and neutrons.

Atomic number is the total number of protons present.

Mass number = protons + neutrons

Atomic number = protons present.

From the above equations we can conclude that,

Atomic number= Mass number- neutrons.

Thus we can find out the atomic number by subtracting the number of neutrons from the mass number.

The Boyle's Law states an inverse relationship between the pressure of a gas and its volume when its temperature stays constant.

For the question

[tex]T_1/T_2 = P_1/P_2[/tex]

Thus

[tex]V_2 = V_1 \cdot (P_1 / P_2) = 0.315[/tex]

We could (a) stir faster and (b) warm the mixture.

Stirring faster moves freshly-dissolved sugar away from the solid and allows new water molecules to contact with the surface,

Warming the mixture gives the water molecules more kinetic energy, so their collisions with the surface of the sugar will be more effective in removing the sugar molecules.

Answer:

The values of Y are: 18, 9, 6, 3, 2, 1

Explanation:

It is given that X and Y are inversely related. This can be depicted mathematically as:

[tex]X \alpha \frac{1}{Y}[/tex]

i.e. as X increases the value of Y is expected to decrease.

(or) [tex]X =k* \frac{1}{Y}[/tex]

where k = proportionality constant which is given as 18

In terms of Y, the above equation becomes:

[tex]Y =k* \frac{1}{X}[/tex]

Based on the above equation the table can be filled as :

X     Y     K

1      18    18

2     9      18

3     6      18

6     3      18

9     2      18

18     1     18

Answer: x y k

1 18 18

2 9 18

3 6 18

6 3 18

9 2 18

18 1 18

Explanation:

The answer is 125 gms.

The correct answer is 2.73.

HF is a weak acid which partially dissociates to release H+ and F-

                HF           →         H⁺   + F⁻

Initial      0.0050                   0       0

Change    -x                        +x       +x

Equilibrium 0.0050–x         +x     +x

Solve by using the equilibrium expression: =  [H⁺] [F⁻]/ [HF]

6 .8 x 10⁻⁴= x. x / 0.0050   –x

6 .8 x 10⁻⁴= x² /0.0050  

x²  = 6 .8 x 10⁻⁴ x 0.0050  

x²  = 3.4 x 10⁻⁶

x = 3.4 x 10⁻⁶

[H⁺]  = 1.84 x 10⁻³

pH = - log [H⁺] = - log (1.84 x 10⁻³)

pH = 2.73

1. A) Bohr

2. D) When excited electrons return back to the ground state, a photon of light is emitted.

3. D) 10.812 amu

Hope this helps! :)

Answer:

1.A

2.D

3.D

Explanation:

1.We have to fill correct answer  in blank  space given in the question.

Bohr's postulates

1.Electron revolve in certain stable  orbits around the nucleus without radiating any energy .The stable orbits or energy levels  are called stationary orbits and these orbits at a certain discrete distance from the nucleus.

2.The stationary orbits are attained at distances for which the  angular momentum is integral multiple of plank;s constant

L=mvr=nh

Where n is called principle quantum number

3.Electrons gain or lose energy when they jump from one energy lever to other energy lever or when higher energy level to low energy level.

Hence, the mystery of periodic laws was solved when Bohr proposed his planetary atomic model of the atom ,providing an understanding of the electronic structure of the elements and the organization of electrons into shells,

Option A is true.

2.When am electron absorb energy then the electrons jump from low energy level to high energy level .When the electron return from higher energy level to low energy level then it emit colored flame.

When Christ put copper chloride into Bunsen burner flame then it began to emit a green color because when excited electron returns back to the ground state , then  photon of light is emitted.

Hence, option D is true.

3.Boron-10 has abundance 19.8% and actual mass of 10.013 amu and boron-11 has an abundance of 80.2% and actual mass of 11.009.

We have to find the average atomic mass for all isotopes of boron

Average atomic mass of boron =[tex]0.198\times 10.013+0.802\times 11.009[/tex]

Average atomic mass of boron=10.811792=10.812 amu

Hence, option D is true.

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".

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).

The relationship is r = 2.5Z + 130.

From your graph, I estimate the slope of the line to be:

[tex]\text{slope} = \frac{\Delta y }{\Delta x } = \frac{260-130}{56-4} = \frac{130}{52} = 2.5\\[/tex]

The y-intercept ≈ 130.

So, the equation for the line is  

r = 2.5Z + 130.

The relation tells us that the atomic size increases as the atomic number increases.

This makes sense because, as you go down a Group, you are adding electrons to the next shell further out.

D. No precipitate will form.

You must recall the pertinent solubility rules:

The only ion not included in the list is Mg²⁺.

However, according to the rules, Mg(NO₃)₂, MgCl₂, and MgSO₄ are soluble.

Thus, there is no precipitate.

According to solubility rules, no precipitate is expected to form from the ions listed in the question (Cl-, K+, Mg²⁺, NO³⁻, SO₄²⁻), the correct answer is D. No precipitate will form.

To determine if a precipitate will form in an aqueous solution containing Cl-, K+, Mg²⁺, NO³⁻, SO₄²⁻, we should apply the solubility rules for ionic compounds. MgSO₄ and K₂SO₄ are generally soluble (Sulfates are generally soluble except for those of barium, calcium, and lead).

MgCl₂, being composed of a Group 2 cation and the chloride anion, is also soluble. However, we must check for the potential formation of a hydroxide precipitate, since that was not explicitly excluded in the original question. Given that hydroxides are typically insoluble except for those of alkali metals and some Group 2 metals (Ca, Sr, and Ba), if hydroxide ions were present, one could expect to see a precipitate of Mg(OH)₂.

However, since the question does not provide information about the presence of hydroxide ions in the solution, and based on the ions listed, no precipitate is expected according to the solubility rules. Therefore, the correct answer is D. No precipitate will form.

Answer : A - carboxyl group.

The carbon in the carboxyl group is bonded to a hydroxyl group and also it is double bonded to an oxygen group.

The carboxyl group when it is dissolved in a solution donates it's hydrogen ion(H+ ion). When it is dissolved in water, the carboxyl group loses its H+ ion to form negatively charged ion.

RCOOH + H2O⇄RCOO- + H3O+

Thus the carboxyl group act as an acid when dissolved in water.

The functional group that acts most like an acid in water is the carboxyl group found in carboxylic acids, due to its ability to release a hydrogen ion and form a carboxylate anion and hydronium ion in solution.

The correct answer to the question of which functional group acts most like an acid in water is A) carboxyl. Carboxylic acids have a carboxyl group, which is made up of a carbonyl (C=O) and a hydroxyl (-OH) group. In water, the hydroxyl group can release a hydrogen ion, making the molecule an acid. Carboxylic acids, like acetic acid, partially dissociate in water to form carboxylate anions and hydronium ions, exhibiting their acidic nature. This is different from hydroxyl groups, which generally act as weak acids and do not donate protons as readily as carboxylic acids.

Count the quantity of each particle in the container in each of the diagrams:

[tex]\begin{array}{cccc} \text{H}_2 & \text{I}_2 & \text{HI} & \\3 & 3 & 0 & \text{as in figure i} \\2 & 2 & 2 & \text{as in figure ii} \\1 & 1 & 4 & \text{as in figure iii} \\1 & 1 & 4 & \text{as in figure iv}\\1 & 1 & 4 & \text{as in figure v} \\\end{array}[/tex]

The container appears to be of constant volume and thus the concentration of each species is directly related to the number of particle present. By definition, the system is in equilibrium once the relative concentration becomes constant, which is in this scenario achieved at the time point depicted in diagram iii. Thus the answer.

the answer is A:

Photosynthesis release O2 (oxygen)

then animals use oxygen for respiration and release Co2

The correct answer is A) Photosynthesis O2 Respiration CO2. Photosynthesis converts CO2 to O2, which is then used in respiration to be converted back into CO2. Both processes together create a continuous cycle.

The correct diagram that represents the cycling of gases between photosynthesis and respiration is A) Photosynthesis O2 Respiration CO2. Through the process of photosynthesis, plants convert carbon dioxide (CO2) and sunlight into oxygen (O2) and glucose. Organisms, including the plants themselves, then use that oxygen for respiration, during which they convert the oxygen back into carbon dioxide. The glucose is used for energy. This continuous cycling plays a critical role in life on Earth.

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