How many grams of sodium bromide must be dissolved in 400.0 g of water to produce a 0.500 molar solution?
A20.0 g
B52.18
C2.00 g
D20.6 g

Answer: 14.625g

Explanation:

No of moles= mass given/molar mass

No of moles given= 0.375mol

Mass is the unknown (?)

Molar mass of K= 39

No of moles = mass given/molar mass

Substitute the values

0.375= mass/39

Cross multiply

Mass = 39×0.375

Mass= 14.625g

The mass is 14.625g

Answer:

14.625g

Explanation:

Mass of a substance =number of moles of the substance × molar mass of the substance

Substance of interest is potassium, K

Given, Number of moles of K =0.375mol

Molar mass of K =39g/mol

Therefore, mass of K =0.375×39=14.625g

Answer:

0.62 L

Explanation:

Step 1:

Data obtained from the question.

Initial Volume (V1) = 1.80 L

Initial pressure (P1) = 785 mmHg

Final pressure (P2) = 3.00 atm

Final volume (V2) =?

Step 2:

Conversion of the pressure in mmHg to atm.

It is important to express the initial and the final pressure in the same unit. Either express both in atm or in mmHg. What ever the case is, we'll still arrive at same answer. Here, we shall be converting from mmHg to atm. This is illustrated below:

760mmHg = 1atm

Therefore, 785 mmHg = 785/760 = 1.03 atm

Step 3:

Determination of the final volume. This is illustrated below.

We shall be applying the Boyle's law equation since the temperature is constant.

P1V1 = P2V2

Initial Volume (V1) = 1.80 L

Initial pressure (P1) = 1.03 atm

Final pressure (P2) = 3.00 atm

Final volume (V2) =?

P1V1 = P2V2

1.03 x 1.8 = 3 x V2

Divide both side by 3

V2 = (1.03 x 1.8) /3

V2 = 0.62 L

Therefore, the new volume of the balloon is 0.62 L

Answer:

The volume of the balloon up there will be 0.618 L

Explanation:

Given:

V₁ = 1.8 L

P₁ = 785 mmHg = 1.03 atm

P₂ = 3 atm

Question: What would the volume of the balloon up there, V₂ = ?

According the ideal gas law:

PV = nRT

However, in this case, the number of moles of helium balloon is constant. The temperature will also be assumed to be constant. Therefore, the expression of the ideal gases is as follows:

P₁V₁ = P₂V₂

Solving for V₂

[tex]V_{2} =\frac{P_{1}V_{1} }{P_{2} } =\frac{1.03*1.8}{3} =0.618L[/tex]

In a study or experiment, the independent variable is what the researcher manipulates and the dependent variable is the response being measured. An example of this would be studying the effect of sunlight (independent variable) on plant growth (dependent variable).

In any experiment or study, the independent variable is the factor that the researcher manipulates or chooses intending to cause a change. It's the variable you have control over. The outcome of this change is observed and measured in the dependent variable. The dependent variable responds to the change you made to the independent variable. For example, if you were studying the effect of varying amounts of sunlight on plant growth. The amount of sunlight would be the independent variable (as you are controlling the amount each plant gets), and the plant growth would be the dependent variable (as you measure it after).

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Answer:

first part of the problem: temperture and volume

second part: tempture and volume

hope this helps

Explanation:

1.38 moles of oxygen

Explanation:

Thermal decomposition of Lead (II) nitrate is shown by the balanced equation below;

2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂

The mole ration of Lead (II) nitrate to oxygen is 2: 1

Therefore 2.76 moles of  Lead (II) nitrate will lead to production of? moles of oxygen;

2: 1

2.76: x

Cross-multiply;

2x = 2.76 * 1

x = 2.76 / 2

x = 1.38

Only the amount of gas is held constant.

Answer:

The weird one that looks like a B is a symbol for a beta ray.

"He" and the infinity looking a represents an alpha particle.

6= Beta ray

7 & 8= alpha particle

Answer:

Hi There The correct answer There are 3 kinds of solar eclipses: total, partial, and annular. There is a rare hybrid that is a combination of an annular and a total eclipse.

Hope it helps!

Answer:

There are 3 kinds of solar eclipses: partial, total, and annular.

A total solar eclipse occurs when the Moon completely covers the Sun, as seen from Earth.

This one happens when the moon covers part of the sun.

An annular solar eclipse occurs when the Moon appears smaller than the Sun as it passes centrally across the sun and leaves a ring of light around the moon.

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Answer:

pH of solution is: 12.82

Explanation:

The reaction of hydrochloric acid with calcium hydroxide is:

Ca(OH)₂ + 2 HCl → H₂O + CaCl₂

Where 2 moles of hydrochloric acid react with 1 mole of calcium hydroxide

Moles of HCl and moles of Ca(OH)₂ are:

Moles HCl:

0.02500L × (0.155mol / L) = 3.875x10⁻³moles HCl

Moles of Ca(OH)₂:

0.03500L × (0.112mol / L) = 3.92x10⁻³moles Ca(OH)₂

Moles of Ca(OH)₂ that react are:

3.875x10⁻³moles HCl × (1 mol Ca(OH)₂ / 2 mol HCl) = 1.9375x10⁻³ mol Ca(OH)₂

Thus, moles of Ca(OH)₂ that remain are:

3.92x10⁻³moles Ca(OH)₂ - 1.9375x10⁻³ mol Ca(OH)₂ = 1.9825x10⁻³ mol Ca(OH)₂

Moles of OH⁻ are:

1.9825x10⁻³ mol Ca(OH)₂ × (2mol OH⁻ / 1mol Ca(OH)₂) = 3.965x10⁻³ mol OH⁻

As volume is 25mL + 35mL = 60mL ≡ 0.060L. Molar concentration of OH⁻ is:

3.965x10⁻³ mol OH⁻ / 0.060L = 0.066M OH⁻.

pOH = -log [OH⁻]

pOH = 1.18

pH = 14-pOH

pH of solution is: 12.82

Answer:

pH = 12.80

Explanation:

Step 1: data given

Volume of a 0.155 M Ca(OH)2 = 25.00 mL = 0.025 L

Volume of a 0.112 M HCl = 35.00 mL = 0.035 L

Step 2: The balanced equation

Ca(OH)2 + 2HCl → CaCl2 + 2H2O

Step 3: Calculate moles

Moles = molarity * volume

Moles Ca(OH)2 = 0.155M * 0.025 L

Moles Ca(OH)2 = 0.003875 moles

Moles HCl = 0.112 M * 0.035 L

Moles HCl = 0.00392 moles

Step 4: Calculate the limiting reactant

For 1 mol Ca(OH)2 we need 2 moles HCl to produce 1 mol CaCl2 and 2 moles H2O

HCl is the limiting reactant. It will completely be consumed. (0.00392 moles) Ca(OH)2 is in excess. There will react 0.00392 / 2 = 0.00196 moles

There will remain 0.003875 - 0.00196 = 0.001915 moles Ca(OH)2

Step 5: Calculate molarity of Ca(OH)2

Molarity = moles / volume

Molarity Ca(OH)2 = 0.001915 moles / (0.060 L)

Molarity Ca(OH)2 = 0.0319 M

For 1 mol Ca(OH)2 we have 2 moles OH-

Molarity of OH- = 2*0.0319 = 0.0638 M

Step 6: Calculate pH

Since Ca(OH)2 is a strong base

The ph will be the pH of a strong base

pOH = -log[0.0638)

pOH = 1.20

pH = 14 -1.20 = 12.80

Answer:

B .

Explanation:

Answer:

D

Explanation:

I tried it and it worked :)

The question pertains to the normal boiling point of a liquid, which is the temperature at which its vapor pressure equals 1 atm (101.3 kPa). Given the vapor pressure is 50 kPa at 40°C, the normal boiling point must be higher than 40°C, making 60°C the correct answer.

The question concerns the normal boiling point of a liquid, which is defined as the temperature at which a liquid’s vapor pressure equals the atmospheric pressure. In a closed system at 40°C, a liquid has a vapor pressure of 50 kPa, but the normal boiling point occurs when its vapor pressure reaches 101.3 kPa, the typical atmospheric pressure. Given that the vapor pressure of the liquid at 40°C is less than 101.3 kPa, and knowing that vapor pressure increases with temperature until it reaches atmospheric pressure (allowing the liquid to boil), the liquid's normal boiling point must be higher than 40°C. Therefore, the answer is (4) 60°C, as it’s the only option provided that is higher than 40°C.

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Answer:

C. Aspirin

Explanation:

If you are using A pex, this is the correct answer.

Reasoning: Soap is not an acid so thats out of the question. I'm not sure if washing soda or antacid are acidic but even if they were, Aspirin is definitely an acid and is way more commonly used than those two.

Answer:

T₂ = 101.13 K OR

- 172.02  °C

Explanation:

Given data:

Initial pressure of gas = 755 Kpa

Initial temperature = 30.0°C

Final temperature = ?

Final pressure = 252 Kpa

Solution;

Initial temperature = 30.0°C (30+273 = 303 K)

According to Gay-Lussac Law,

The pressure of given amount of a gas is directly proportional to its temperature at constant volume and number of moles.

Mathematical relationship:

P₁/T₁ = P₂/T₂

Now we will put the values in formula:

755 Kpa / 303 K = 252 Kpa / T₂

T₂ = 252 Kpa ×303 K / 755 Kpa

T₂ = 76356 KPa.K / 755 Kpa

T₂ = 101.13 K

Kelvin to °C:

101.13 K - 273.15 = - 172.02  °C

Answer:

A. the atomic number

Explanation:

It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth.

The question is incomplete. The complete question is:

15L tank of gas is contained at a high pressure of [tex]8.20\times 10^4 torr[/tex]. The tank is opened and the gas expands into an empty chamber with a volume of [tex]6\times 10^4 L. What is the final pressure if the temperature remains constant.

Answer: 20.5 torr

Explanation:

To calculate the new pressure, we use the equation given by Boyle's law. This law states that pressure is directly proportional to the volume of the gas at constant temperature.

The equation given by this law is:

[tex]P_1V_1=P_2V_2[/tex]

where,

[tex]P_1\text{ and }V_1[/tex] are initial pressure and volume.

[tex]P_2\text{ and }V_2[/tex] are final pressure and volume.

We are given:

[tex]P_1=8.20\times 10^4torr\\V_1=15L\\P_2=?\\V_2=6\times 10^4L[/tex]

Putting values in above equation, we get:

[tex]8.20\times 10^4\times 15L=P_2\times 6\times 10^4L\\\\P_2=20.5torr[/tex]

Thus new pressure will be [tex]20.5torr[/tex]

In pulling up a bucket of water, Harry uses chemical energy converted into mechanical energy, which transforms into gravitational potential energy as the bucket rises.

When Harry pulls up the bucket of water from the well using a pulley, a number of energy transformations occur. Initially, he uses the chemical energy in his body (obtained from the food he eats) to apply mechanical energy to the system (pulley and bucket). As the bucket begins to rise, the mechanical energy is transformed into gravitational potential energy. This is similar to water at a higher elevation having a higher potential energy than water at a lower elevation.

This process demonstrates a key principle in physics: energy is conserved and can be transferred or transformed from one form to another, but is never lost. So in this case, the chemical energy in Harry's muscles is converted into mechanical energy, which in turn is transformed into gravitational potential energy as the bucket is lifted higher in the well.

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Answer: 0.53g

Explanation:

No of moles= volume ×molarity/1000

We have the volume and the molarity

Volume=4L

Molarity=1.7M

No of moles = 4×1.7/1000

No of moles= 0.0068moles

Remember also that

No of moles= mass given/molar mass

Molar mass of Al(OH)3

Al= 27

O=16

H=1

Molar mass = Al+(O+H)3

Molar mass= 27+(16+1)3

Molar mass= 27+(17)3

Molar mass = 27+51

Molar mass= 78g/mol

To get the mass

Mass given = no of moles × molar mass

Mass= 0.0068×78

Mass= 0.53g

Answer:

Any scientific theory must be based on a careful and rational examination of the facts. Facts and theories are two different things. In the scientific method, there is a clear distinction between facts, which can be observed and/or measured, and theories, which are scientists' explanations and interpretations of the facts.

Explanation:

A scientific theory is an explanation of an aspect of the natural world that can be repeatedly tested and verified in accordance with the scientific method, using accepted protocols of observation, measurement, and evaluation of results.

Answer:

B. Rocks can be formed and altered by the activity of organisms

Explanation:

Answer:

2.09 atm

Explanation:

We can solve this problem by using the equation of state for an ideal gas, which relates the pressure, the volume and the temperature of an ideal gas:

[tex]pV=nRT[/tex]

where

p is the pressure of the gas

V is its volume

n is the number of moles

R is the gas constant

T is the absolute temperature

In this problem we have:

n = 0.65 mol is the number of moles of the gas

V = 8.0 L is the final volume of the gas

[tex]T=40C+273=313 K[/tex] is the temperature of the gas

[tex]R=0.082 atm L mol^{-1} K^{-1}[/tex] is the gas constant

Solving for p, we find the final pressure of the gas:

[tex]p=\frac{nRT}{V}=\frac{(0.65)(0.082)(313)}{8.0}=2.09 atm[/tex]

0.65 moles of O₂ at 40. °C and 2.1 atm occupy a volume of 8.0 L.

0.65 moles (n) of O₂ originally at 85°C is cooled. It occupies 8.0 L (V) at 40.°C (T). We will convert the final temperature to Kelvin using the following expression.

[tex]K = \°C + 273.15 = 40\°C + 273.15 = 313 K[/tex]

We can calculate the final pressure (P) exerted by the gas using the ideal gas equation.

[tex]P \times V = n \times R \times T\\\\P = \frac{n \times R \times T}{V} = \frac{0.65 mol \times (\frac{0.082atm.L}{mol.K} ) \times 313K}{8.0L} = 2.1 atm[/tex]

0.65 moles of O₂ at 40. °C and 2.1 atm occupy a volume of 8.0 L.

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Answer:

83.60oC per cal

Explanation:

The amount of heat required to raise the temperature of 57.8g of silver from 17.0°C to 43.5°C is 87.31 calories.

The energy required to raise the temperature of a substance can be calculated using the following formula:

Q = m × c × ∆T

Where;

Q = 57.8 × 0.057 × (43.5 - 17)

Q = 87.31calories

Therefore, the amount of heat required to raise the temperature of 57.8g of silver from 17.0°C to 43.5°C is 87.31 calories.

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Answer:

The pH of the solution is 2.60.

Explanation:

The pH gives us an idea of the acidity or basicity of a solution. More precisely, it indicates the concentration of H30 + ions present in said solution. The pH scale ranges from 0 to 14: from 0 to 7 corresponds to acid solutions, 7 neutral solutions and between 7 and 14 basic solutions. It is calculated as:

pH = -log (H30 +)

pH= -log (0,0025)

pH=2.60

Answer:

it mainly  depends what state of lithium chloride that you use to electrolysis, if you choose the aqueous state of lithium chloride then you'll have a produce of chlorine and oxygen at the anode, lithium and hydrogen is produce at the cathode but lithium will react with water to form lithium hydroxide

Explanation:

Final answer:

The electrolysis of molten lithium chloride results in the formation of lithium metal at the cathode and chlorine gas at the anode, involving the direct conversion of chemical energy into electrical energy through electrolysis.

Explanation:

The question is about describing the electrolysis of molten lithium chloride to produce lithium and chlorine gas. The process of electrolysis involves passing an electric current through molten lithium chloride (LiCl), resulting in the formation of lithium metal (Li) and chlorine gas (Cl₂). This process takes place in an electrolytic cell.

Overall reaction: 2LiCl(l) → 2Li(s) + Cl₂(g)

At the cathode: Li⁺ + e⁻ → Li(s)

At the anode: 2Cl⁻ → Cl₂(g) + 2e⁻

These reactions demonstrate the principle of electrochemistry where chemical energy is converted into electrical energy, and vice versa. The electrolysis of molten lithium chloride is an efficient way to produce pure lithium metal and chlorine gas, which have various applications in industries.

Answer:

V₂ =19.30 L

Explanation:

Given data:

Initial volume of gas = 29.3 L

Initial temperature = standard = 273 K

Initial pressure = standard = 1 atm

Final volume = ?

Final temperature = -23°C (-23+273 =250 K)

Final pressure = 1.39 atm

Solution:

Formula:  

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

Solution:

V₂ = P₁V₁ T₂/ T₁ P₂  

V₂ = 1 atm × 29.3 L × 250 K / 273 K × 1.39 atm

V₂ = 7325 atm.L.K / 379.47 K.atm

V₂ =19.30 L

Answer:

True

Explanation:

Answer:

by increasing the temperature

Answer:

0.5 L

Explanation:

V1 (initial volume) = 4 L

P1 (initial pressure)  = 2.5 kPa

P2 (final pressure) = 20 kPa

V2 (final volume) = ?

Use Boyle's law  P1V1 = P2V2, to find the the final volume

P1V1 = P2V2

2.5 x 4 = 20 x V2

Divide both side by 20

V2 = (2.5 x 4)/20

V2 = 0.5 L

Answer: 0.5L

Explanation:

Using Boyle's law

P1V1=P2V2

P1= 2.5kpa

V1= 4l

V2= ?

P2= 20.0kpa

Substitute the value into this formula

P1V1=P2V2

2.5×4=20×V2

Cross multiply

2.5×4=20V2

V2= 2.5×4/20

V2= 80/2.5

V2= 0.5L

So 0.5L of gas will occupy 20.0kpa

Answer:

heat content

Explanation:

the kinetic energy , distance between molecules, and potential energy are all depending on the substance

Answer: 3.68 x 10^21 particles

Explanation:

Based on Avogadro's law:

1 mole of any substance has 6.02 x 10^23 atoms

Since 1 mole is the same as molar mass of a substance

237 g = 6.02 x 10^23 atoms

1.45g = Z atoms

To get the value of Z, cross multiply:

(Z atoms x 237g) = (6.02 x 10^23 atoms x 1.45g)

237Z = 8.729 x 10^23

Z = (8.729 x 10^23 / 237)

Z = 3.68 x 10^21

Thus, there are 3.68 x 10^21 representative particles in 1.45 g of the molecular compound.

To find the number of representative particles in 1.45 g of a substance with a molar mass of 237 g/mol, first calculate the number of moles by dividing the mass by the molar mass, then multiply by Avogadro's number. The calculation shows there are approximately 3.69 × 10²± representative particles.

To calculate the number of representative particles in 1.45 g of a molecular compound with a molar mass of 237 g/mol, we need to use Avogadro's number and the concept of molar mass.

First, we determine the number of moles in 1.45 g:

Number of moles = mass (g) / molar mass (g/mol) = 1.45 g / 237 g/mol.

After finding the number of moles, we use Avogadro's number (6.02 × 10²³ particles/mol) to find the number of representative particles:

Number of particles = number of moles × Avogadro's number.

Therefore, we would calculate:

1.45 g / 237 g/mol = 0.0061180 moles.

Number of particles = 0.0061180 moles × 6.02 × 10²³ particles/mol.

After performing the multiplication, we find:

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The strong acid and strong base has high rate constant of dissociation. Weak acid and base are the one whose rate constant for the dissociation is low, they do not dissociate readily in water. The red cabbage juice can be used to determine the strength of acids and bases.

Acid is a solution which releases H⁺ hydrogen ion when dissolved in water. Base are the solution which releases hydroxide ion OH⁻ ion when dissolved in water

Red cabbage juice contain a pigment called anthocyanin. Acidic solutions turns purple color of anthocyanin red. Basic solutions turns purple color of anthocyanin greenish-yellow. There will be no change in color in neutral solution.

Therefore, red cabbage juice can be used to determine the strength of acids and bases.

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Answer:

3. The rate of formation of the products must equal the rate of formation of the reactants.

Explanation:

The reaction at the equilibrium represents the rate of formation of the products that is equivalent to the rate of formation of the reactants.

It is arise at the equilibrium at the time when the amounts of reactants or products should be same. The Chemical equilibrium refers to the dynamic process that represent the rate of formation of products via the forward reaction i.e. equivalent to the rate where the products should be reform reactions via the reverse reaction.

hence, the option 3 is correct.

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