which of the following best describes precision

Answer:

the total I think would be 35

Answer:

identical conditions, separate samples of O2 and an unknown gas were allowed to effuse through identical membranes simultaneously. After a certain amount of time, it was found that 6.23 mL of O2 had passed through the membrane, but only 3.85 mL of of the unknown gas had passed through. What is the molar mass of the unknown gas

identical conditions, separate samples of O2 and an unknown gas were allowed to effuse through identical membranes simultaneously. After a certain amount of time, it was found that 6.23 mL of O2 had passed through the membrane, but only 3.85 mL of of the unknown gas had passed through. What is the molar mass of the unknown gas

Explanation:

identical conditions, separate samples of O2 and an unknown gas were allowed to effuse through identical membranes simultaneously. After a certain amount of time, it was found that 6.23 mL of O2 had passed through the membrane, but only 3.85 mL of of the unknown gas had passed through. What is the molar mass of the unknown gas

Answer:

HPO₄⁻² +  H₂O  ⇄  PO₄⁻³  + H₃O⁺       Ka3

Explanation:

Phosphoric acid, H3PO4 is a dyprotic acid which undergoes in these three succesive ionization reactions.

The last equillibrium is conditionated to the Ka3

H₃PO₄  +  H₂O  ⇄  H₂PO₄⁻  + H₃O⁺     Ka1

H₂PO₄⁻  +  H₂O  ⇄  HPO₄⁻²  + H₃O⁺   Ka2

HPO₄⁻² +  H₂O  ⇄  PO₄⁻³  + H₃O⁺       Ka3

It is an acid because it release a proton, to make the [H₃O⁺] rise.

pH of solution will always be < 7

H₂PO₄⁻  and  HPO₄⁻²  are amphoteric compounds, which means that they can work as an acid (release protons), or base (take protons)

Answer:

b. pH=12

Explanation:

Step 1: Given data

Concentration of NaOH: 0.01 mol/dm³ = 0.01 mol/L = 0.01 M

Step 2: Write the reaction for the dissociation of NaOH

NaOH is a strong base that dissociates according to the following equation.

NaOH(aq) ⇒ Na⁺(aq) + OH⁻(aq)

The molar ratio of NaOH to OH⁻ is 1:1. Then, the concentration of OH⁻ is 0.01 M.

Step 3: Calculate the pOH

pOH = -log [OH⁻] = -log 0.01 = 2

Step 4: Calculate the pH

We will use the following expression.

pH + pOH = 14

pH = 14 - pOH = 14 -2 = 12

Answer:

The correct answer is option C, that is, ΔS and ΔSsurr for the process H2O (s) ⇒ H2O(l) are equal in magnitude and opposite in sign.

Explanation:

The temperature at which solid state of water get transformed into liquid state is termed as the melting point of 0 °C. It can be shown by the reaction:  

H2O (s) ⇒ H2O (l)

The degree of randomness of a molecule is known as entropy. With the transformation of ice into liquid state, there is an increase in randomness. Thus, the value of entropy becomes positive as shown:  

Entropy change (ΔSsys) = ΔSproduct - ΔSreactant

= (69.9 - 47.89) J mol/K

= 22.0 J mol/K

Therefore, the value of entropy change is positive.  

Now the value of entropy for surrounding ΔSsurr will be,  

ΔSsurr = -ΔHfusion/T  

= -6012 j/mol/273

= -22.0 J/molK

Hence, the value of ΔSsurr and ΔSsys exhibit same magnitude with opposite sign.  

Answer:

Explanation:

We can only talk about resonance hybrid for a compound in which more than one structure is possible based on its observed chemical properties.

There are compounds whose chemical properties can not be satisfactorily explained on the basis of a single chemical structure. In the case of such compounds, we invoke the idea of resonance.

A resonance hybrid is a single structure drawn to represent a given chemical specie which exhibits resonance behaviour and can otherwise be represented on paper in the form of an average of two or more chemical structures separated each from the next by a double-headed arrow.

Answer:

Resonance hybrids are best defined as a molecule's electron pattern cannot be described by a single structure.

Explanation:

its right

the products formed from the reaction

all of the above

Answer:

33.85°C

Explanation:

From the question,

Heat lost by the hotter water = heat gained by the colder water

cm'(t₂-t₃) = cm(t₃-t₁)................. Equation 1

Where c = specific heat capacity of water, m' = mass of hot water, m = mass of cold water, t₁ = Initial temperature of cold water, t₂ = Initial temperature of hot water, t₃ =  final temperature of the mixture.

But since the density of water is constant, and mass varies directly as volume, We can replace the mass of water with the volume of water. i.e,

cv'(t₂-t₃) = cv(t₃-t₁)................. Equation 2

Where v' and v are the volume of hot water and cold water respectively

make t₃ the subject of the equation

t₃ = (v't₂+vt₁)/(v'+v)............ Equation 3

Given: v' = 5.0 L, v = 60 L, t₁ = 30°C, t₂ = 80°C

Substitute these values into equation 3

t₃ = (5×80+60×30)/(60+5)

t₃ = 2200/68

t₃ = 33.85°C

Answer:

3,5-dichlorohex-1-ene

Explanation:

The compound is; H2C=CH-C(Cl)H-CH2-C(Cl)H-CH3. We can rightly call this compound by the name, 3,5-dichlorohex-1-ene.

We arrived at this name by first counting the longest parent carbon chain, that gives hexane. The compound has a double bond at the 1-position. Also, there are two substituent chlorine atoms at positions 3 and 5 in the structure, hence the name given.

Answer:

Weight is a noun that means a human body's mass.

For example: Joh is 168 pounds.

This is the correct definition of weight.

Here to help!

Answer:

You would use an electrolytic cell.

Answer:

b) The boiling point of the solution is always greater than the boiling point of the pure solvent.

Explanation:

Hello,

In this case, when we add a nonvolatile solute to a volatile solvent which has a relatively low boiling point, we can evidence the increase of the boiling point of the resulting solution as more energy must be supplied to take the molecules from liquid to gas. This fact matches with the boiling point elevation colligative property due to the solute's addition, which states that the boiling point of the solution is always greater than the boiling point of the pure solvent, therefore, answer is b).

Best regards.

The statement true about the solution made from a nonvolatile solute and a volatile solvent is, the boiling point of the solution is always greater than the boiling point of the pure solvent. Thus option C is correct.

The boiling point of the solution can be defined as the temperature where the liquid has been converted to the gaseous state. In the solvent, the energy has been provided to the sample for the conversion of liquid molecules to gas.

The addition of a nonvolatile solute to the volatile solvent results in the addition of the molecules to the solvent. This will result in the requirement of more energy for the conversion of solvent from a liquid state to a gaseous state.

Thus, with the addition of a nonvolatile solute to the volatile solvent, the boiling point of the solution will be increased and will always be greater than the boiling point of the pure solvent.

Thus option C is correct.

For more information about the volatile solvent, refer to the link:

https://brainly.com/question/3013635

Answer: The scientific method attempts to minimize the influence of bias or prejudice in the experimenter. Even the best-intentioned scientists can't escape bias. ... That's the job of the scientific method. It provides an objective, standardized approach to conducting experiments and, in doing so, improves their results.

Answer:

B. CH3CH2OH

Explanation:

Ethanol has a chemical formula of CH3CH2OH, it is the second member of the series in the alkanol family. Ethanol is a colourless, volatile liquid with a characteristic smell and taste. It is readily soluble in water in all proportions. It has a boiling point of 78° C. The physical properties such as the solubility of alkanols are affected by the presence of hydrogen bonding. The hydroxyl group is capable of bonding to other alkanol molecules. The boiling points rise with increasing molecular mass.

    Hydrogen bonding helps the molecules to stick together. For example comparing the boiling point of pentane ( 36° C) with that of butan-1-ol (118° C) , the boiling point of alkanol is much higher even though the two compound are of similar relative molecular mass. This is due to the presence of hydrogen bonds in butanol.

    Hydrocarbons are not soluble in water but alkanols are soluble in water because of the hydroxyl groups in the molecules can form hydrogen bond with water. Solubility of alkanol in water decreases as the number of carbon atom increases. Primary alcohol with more than five carbon atoms are insoluble in water.

Answer:

2 lone pairs of electrons

Explanation:

In this case, the central atom is oxygen. If we check the periodic table we will have an atomic number of 8. So, the electronic configuration would be:

[tex]1s^2~2s^2~2p^4[/tex]

We have 6 electrons in the last level. Therefore, we have 6 valence electrons. For the hydrogens, we will have only 1 electron each. So, in total, we have 8 electrons.

With this in mind, we have to draw two lone pairs in the oxygen and 1 bond with each hydrogen.

See figure 1.

I hope it helps!

Answer:

See explanation below.

Explanation:

We can obtain the Gibb's free energy from the formula;

∆G= ∆H - T∆S

Where;

∆G = change in free energy= the unknown

∆H= change in enthalpy = 3352 kJ

∆S= change in entropy of the solution= 625.1 J/K

T= absolute temperature = 298 K

Substituting values;

∆G= 3352 ×10^3 J - (298 K × 625.1 J/K)

∆G= 3352 ×10^3 J - 186279.8

∆G= 3.16 × 10^6 J

At 5975K,

∆G= ∆H - T∆S

∆G= 3352 ×10^3 J - (5975K × 625.1 J/K)

∆G= 3.352 ×10^6 J - 3.735 × 10^6

∆G= -3.83×10^5 J

At equilibrium, ∆G=0, Teq is given by;

0= 3352 ×10^3 J - (Teq × 625.1 J/K)

0= 3352 ×10^3 - 625.1Teq

625.1Teq = 3352 ×10^3

Teq= 3352 ×10^3/625.1

Teq= 5362.3 K

Standard Gibb's free energy at 298 & 5975K is 3.16×10⁶J and -3.83×10⁵J respectively, and temperature at equilibrium state is 5362.3 K.

Standard Gibb's free energy of any reaction will be calculated as:
∆G° = ∆H° - T∆S°, where

∆G° = change in free energy = to find?

∆H° = change in enthalpy = 3352 kJ = 3,352 × 10³J

∆S° = change in entropy = 625.1 J/K

T = absolute temperature = 298 K

On putting all these values on the above equation, we get

∆G° = (3,352 × 10³) - (298 × 625.1) = 3.16 × 10⁶J

Gibb's free energy at 5,975 K temperature:

∆G° = (3,352 × 10³) - (5,975 × 625.1) = -3.83 × 10⁵J

At the equilibrium state value of Gibb's free energy is zero, so from the equation and given data we can calculate the value of temperature as:

0 = (3352 × 10³)J - (T × 625.1 J/K) = 5362.3 K

Hence required values are 3.16 × 10⁶J, -3.83 × 10⁵J and 5362.3 K.

To know more about Gibb's free energy, visit the below link:

https://brainly.com/question/9908454

Answer:

2.41 × 10²⁰ atoms

Explanation:

Step 1: Given data

Step 2: Convert the mass of the sample to grams

We will use the relationship 1 g = 1,000 mg.

38.3 mg × (1 g/1,000 mg) = 0.0383 g

Step 3: Calculate the number of atoms in 0.0383 g of molybdenum

0.0383 g × (1 atom/1.59 × 10⁻²² g) =  2.41 × 10²⁰ atom

Answer:

Metal C

Explanation:

Density = mass (g)/ volume (mL, which is the same thing as cm cubed)

Divide mass by volume for each metal, the metal with the lowest value (metal C) is your answer.

Answer:

IT IS

NOT. I REPEAT - IT IS NOT> D

Explanation:

i got it wrong :(

Answer:

20 hydrogen atoms in 5 moles of methyl alcohol.

Explanation:

Hi!

So, there are 4 hydrogen atoms in 1 mole of methyl alcohol. If you multiply 4*5, it equals to 20.

Have a great day!

Answer:

7,052.6secs

Explanation:

n of Cu = +2

R.A.M of Cu = 64g

m = 7.25g

I = 3.1A

F = 96500

nF = R.A.M

It = m

2*96500 = 64

3.1*t = 7.25

1,399,250 = 198.4t

t = 7,052.6secs

Answer:

1. Balanced Molecular equation

Ca(OH)2(aq) + 2HCl(aq) —> CaCl2(aq) + 2H2O(aq)

2. Net ionic equation

OH-(aq) + H+(aq) —> H2O(l)

Explanation:

1. Molecular balance equation for the reaction between Ca(OH)2(aq) and HCl(aq).

This is illustrated below:

Ca(OH)2(aq) + HCl(aq) —> CaCl2(aq) + H2O(aq)

There are 2 atoms of Cl on the right side and 1 atom on the left side. It can be balance by putting 2 in front of HCl as shown below:

Ca(OH)2(aq) + 2HCl(aq) —> CaCl2(aq) + H2O(aq)

There are 2 atoms of H on the right side and a total of 4 atoms on the left side. It can be balance by putting 2 in front of H2O as shown below:

Ca(OH)2(aq) + 2HCl(aq) —> CaCl2(aq) + 2H2O(aq)

Therefore the equation above is balanced.

2. Net ionic equation for the reaction between Ca(OH)2(aq) and HCl(aq).

In solution, Ca(OH)2(aq) and HCl(aq) will dissociate as follow:

Ca(OH)2(aq) —> Ca2+(aq) + 2OH-(aq)

HCl(aq) —> H+(aq) + Cl-(aq)

Ca(OH)2(aq) + 2HCl(aq) —>

Ca2+(aq) + 2OH-(aq) + 2H+(aq) + 2Cl-(aq) —> Ca2+(aq) + 2Cl-(aq) + 2H2O(l)

Cancel out the spectator ions i.e Ca2+ and Cl- to obtain the net ionic equation

2OH-(aq) + 2H+(aq) —> 2H2O(l)

OH-(aq) + H+(aq) —> H2O(l)

Answer:

NO.

Explanation:

The rate of diffusion of gases is inversely proportional to the square root of its density as explained by Graham's law of diffusion i.e

Rate (R) & 1/√(density (d))

R & 1/√d

But the density of a gas is proportional to the molar mass (M) of the gas.

Thus, the above equation can written as:

R & 1/√d

R & 1/√M

This implies that rate is inversely proportional to the molar mass of a gas i.e the lighter the gas, the faster the rate and the heavier the gas, the slower the rate of diffusion.

Now, to obtain the answer to the question, let us determine the molar mass of each gas.

This is illustrated below:

Molar mass of Kr = 84 g/mol

Molar mass of NO = 14 + 16 = 30 g/mol

Molar mass of Ar = 40 g/mol

Molar mass of N2O = (14x2) + 16 = 44 g/mol

Summary

Gas >>>>>>> Molar mass

Kr >>>>>>>>> 84 g/mol

NO >>>>>>>> 30 g/mol

Ar >>>>>>>>> 40 g/mol

N2O >>>>>>> 44 g/mol

From the above table, we can see the lightest gas is NO.

Therefore, NO will escape through the hole in the balloon at the highest rate.

Answer:

The sun warms up parts of the oceans. Warm waters rise just like warm air rises. So, as the warmer ocean waters begin to rise in a particular area, the cooler ocean waters from a different area will move in to replace the warmer ocean waters, and this creates our ocean currents.

Hope it helps!

Answer:

The answer of the scientific STATEMENT is" Appears That Ants Live In Colonies."

Answer:

ask a teacher is the correct answer.

Explanation:

You must ALWAYS ask a teacher if you are not sure about what to do during a lab activity.

Answer:

It's important to ask the teacher, lab safety policies all state that if you're confused about instructions it's always good to ask the teacher to clarify them.

Answer:

C

Explanation:

Tertiary alcohol should be the answer.

This is because tertiary alcohol has a less polar compound which means it is less likely to have chemical reaction with other compounds whereas primary and secondary alcohol has a higher chance of having chemical reaction with other compounds.

Answer:

I think the answer is A

Explanation:

primary alcohol has only one methyl group bonded to the central carbon atom, and the extent of decrease in partial posative charge is less, making it more prone to attack by nucleophiles. thus tertiary alcohols are more stable than primary alcohols

Answer:

In solving this question it is important to note that entropy is referred to as the degree of randomness in a compound or system.

Entropy is highest in gas and lowest in solids

The order is given as:

Gas > Liquid > Solid

Another criteria is the more the elements in a compound, the more the entropy.

For example: KO3 has more entropy than KO2 due to the presence of more elements.

The last criteria is calculating their masses , the one with a greater mass has the higher entropy.

The option with the least entropy will be a solid. Al(s) and NaF(s) are both solids. NaF(s) has more elements in a compound which makes it have a higher entropy than Al(s). This means NaF(s) > Al(s).

The next to consider are the gaseous compounds which are HF(g) , SiF4(g) and SiH4(g). The least entropy will be HF(g) . This is because it has the least number of elements of the 3 compounds.

SiF4(g) and SiH4(g) have equal number of elements in a compound but the one with the highest mass is SiF4(g) because fluorine has a higher mass when compared to hydrogen. This means the compound with the highest entropy is SiF4(g).

The order of increasing entropy is given below:

Al(s) < NaF(s) < HF(g) < SiH4(g) < SiF4(g)

Answer:

I don't know the second one but one of them is Aristotle

Answer:

Aristrotle and John Dalton

Explanation:

Answer:

Molality, Solvent, Solute, Mole fraction, Molarity.

Explanation:

The expression of concentration that provides the moles of solute per kilograms of solvent is Molality.  This in the only expression referred to the solvent.

A solution is made up of 0.15 grams of sodium chloride in 1 liter of water. For this solution, the Solvent is water.  When water is present, it is usually considered the solvent.

A solution is made up of 0.15 grams of sodium chloride in 1 liter of water. For this solution, the Solute is sodium chloride.  There can be 1 or more solutes in a solution.

If you place 5 moles of sodium chloride and 4 moles of sucrose into 11 moles of water, the Mole fraction of sodium chloride would be 0.25.  The mole fraction is equal to the moles of a substance divided by the total number of moles.

A way to express concentration that provides the moles of solute per liter of solution is Molarity.