Categories
Assignment Help

An 8.65-g sample of an unknown group 2a metal hydroxide is dissolved in 85.0 ml of water. an acid-base indicator is added and the resulting solution is titrated with 2.50 m hcl(aq) solution. the indicator changes color signaling that the equivalence point has been reached after 56.9 ml of the hydrochloric acid solution has been added.

[ad_1]

Answer;

The molar mass of metal hydroxide = 121.66 g/ mole

The formula is Sr(OH)2

Explanation;

M(OH)2 + 2 HCl = MCl2 + 2 H2O  

Moles of the acid = 2.5 x 56.9 / 1000 = 0.14225  

Therefore; moles of hydroxide at the eq point = 0.0711 moles  

These have a mass of 8.65g

Thus; mass of 1 mole = 8.65 / 0.0711

         = 121.66 g / mole  

That means the compound is Sr (OH)2 ..

[ad_2]

Categories
Assignment Help

Which of the following would not be considered a solution A) Sand in water B) Sugar dissolved in water C) Vinegar mixed with water D) Seawater

[ad_1]

This problem is to apply Roult’s Law.

Roult’s Law states that the vapor pressure, p, of a solution of a non-volatile solute is equal to the vapor pressure of the pure solvent, Po solv, times the mole fraction of the solvent, Xsolv

p = Xsolv * Po sol

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

Answer: 30.6 torr

[ad_2]

Categories
Assignment Help

When 13.6 grams of kcl are dissolved in enough water to create a 180-gram solution, what is the solution’s concentration, expressed as a percent by mass? 4.6% kcl 6.8% kcl 7.6% kcl 8.2% kcl?

[ad_1]

This problem is to apply Roult’s Law.

Roult’s Law states that the vapor pressure, p, of a solution of a non-volatile solute is equal to the vapor pressure of the pure solvent, Po solv, times the mole fraction of the solvent, Xsolv

p = Xsolv * Po sol

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

Answer: 30.6 torr

[ad_2]

Categories
Assignment Help

Write the net ionic equation for the equilibrium that is established when ammonium perchlorate is dissolved in water.

[ad_1]

Explanation :

In the net ionic equations, we are not include the spectator ions in the equations.

Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.

(a) The given balanced ionic equation is,

Ni(NO_3)_2(aq)+Na_2S(aq)rightarrow NiS(s)+2NaNO_3(aq)

The ionic equation in separated aqueous solution will be,

Ni^{2+}(aq)+2NO_3^-(aq)+2Na^+(aq)+S^{2-}(aq)rightarrow NiS(s)+2Na^+(aq)+2NO_3^-(aq)

In this equation, Na^+text{ and }NO_3^- are the spectator ions.

By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.

The net ionic equation will be,

Ni^{2+}(aq)+S^{2-}(aq)rightarrow NiS(s)

(b) The given balanced ionic equation is,

NaNO_3(aq)+KBr(aq)rightarrow KNO_3(s)+NaBr(aq)

The ionic equation in separated aqueous solution will be,

Na^+(aq)+NO_3^-(aq)+K^+(aq)+Br^-(aq)rightarrow KNO_3(s)+Na^+(aq)+Br^-(aq)

In this equation, Na^+text{ and }Br^- are the spectator ions.

By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.

The net ionic equation will be,

NO_3^-(aq)+K^+(aq)rightarrow KNO_3(s)

(c) The given balanced ionic equation is,

Li_2SO_4(aq)+BaCl_2(aq)rightarrow BaSO_4(s)+2LiCl(aq)

The ionic equation in separated aqueous solution will be,

2Li^+(aq)+SO_4^{2-}(aq)+Ba^{2+}(aq)+2Cl^-(aq)rightarrow BaSO_4(s)+2Li^+(aq)+2Cl^-(aq)

In this equation, Li^+text{ and }Cl^- are the spectator ions.

By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.

The net ionic equation will be,

SO_4^{2-}(aq)+Ba^{2+}(aq)rightarrow BaSO_4(s)

[ad_2]

Categories
Assignment Help

Suppose you dissolved 0.123 gram of pentane in 2.493 grams of p-xylene and measured a freezing point depression of 2.88 degrees celcius for the solution. Calculate the molar mass of pentane using this data and the value for Kf that you calculated in question 1 I got .829 mol/kg for question 1

[ad_1]

This problem is to apply Roult’s Law.

Roult’s Law states that the vapor pressure, p, of a solution of a non-volatile solute is equal to the vapor pressure of the pure solvent, Po solv, times the mole fraction of the solvent, Xsolv

p = Xsolv * Po sol

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

Answer: 30.6 torr

[ad_2]

Categories
Assignment Help

The molality of a solution that is made by dissolving a certain mass of benzene in 20.6 g of carbon tetrachloride is 0.529 m. How many moles of benzene were dissolved?

[ad_1]

This problem is to apply Roult’s Law.

Roult’s Law states that the vapor pressure, p, of a solution of a non-volatile solute is equal to the vapor pressure of the pure solvent, Po solv, times the mole fraction of the solvent, Xsolv

p = Xsolv * Po sol

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

Answer: 30.6 torr

[ad_2]

Categories
Assignment Help

Areas near oceans or large lakes tend to have more moderate climates than do areas far from large bodies of water. Which of these statements best explains this observation? Hydrogen and oxygen atoms share electrons in a water molecule. Lakes and oceans contain dissolved solids. Water has a very high specific heat. Water produces buoyant forces. Question 2(Multiple Choice Worth 2 points) A scientist discovers a new substance. The molecules of the substance form hydrogen bonds with each other. When the molecules lose a lot of energy, the hydrogen bonds hold them relatively far apart. Based on this information, what can the scientist infer about the substance? It expands when it freezes. It is highly colored. It exists only as a gas. It does not dissolve ionic compounds. Question 3(Multiple Choice Worth 2 points) Which of the following properties of water is due primarily to the uneven distribution of charge between the hydrogen and oxygen atoms? its color its taste its ability to dissolve ionic substances its ability to produce buoyant forces Question 4(Multiple Choice Worth 2 points) A drop of water placed on a smooth, dry surface will form a dome-shaped droplet instead of flowing outward in different directions. Which of these best explains this observation? The bonds between hydrogen and oxygen atoms are very strong. The electrons in the atoms attract the electrons in the other atoms. Water molecules at the surface experience fewer hydrogen bonds than water molecules within the liquid. Water molecules near the surface produce more buoyant force than water molecules within the liquid.

[ad_1]

The gravitational force Fg between two objects is given by the equation:

Fg=(G*m₁*m₂)/r₂, where G=6.67*10^-11 m³ kg⁻¹ s⁻² is the gravitational constant, m₁ and m₂ are the masses of the two bodies and r is the distance between those bodies. 

Due to the gravitational attraction the pencil and the eraser will attract if we there is no friction on the surface. 

m₁=10 g=0.01 kg is the mass of the pencil
m₂=20 g=0.02 kg is the mass of the eraser
r=2.5 cm = 0.025 m

First we calculate the Fg:

Fg={(6.67*10^-11)*0.01*0.02}/(0.025²)=2.1344*10^-11 N

To get the velocity v of the pencil:

v²=2as, where a is the acceleration of the pencil and s is the path. In our case s=r so we can write:

v²=2ar

a=Fg/m₁= 2.133*10^-9 m/s²

v²=2*(2.133*10^-9)*0.025=1.0665*10^-10

v=√(1.0665*10^-10)=1.0327*10^-5 m/s

We have the velocity and the acceleration, so we can calculate the time t with the equation:

t=v/a=(1.0327*10^-5)/(2.133*10^-9)=4841.6 s

1 hour has 3600 s so when we divide time t in seconds by 3600 we get time T in hours:

T=t/3600=4841.6/3600=1.3449 h. 

So the time for the pencil and eraser to touch is T=1.3449 hours. 

Also time T can be expressed like T= 1h and 20 mins and 41.64 s

[ad_2]

Categories
Assignment Help

14 g of sugar is dissolved in 100 mL of water. What is the mass of the new system? Question 2 options: a) 114 g b) 100 g c) 86 g d) 107 g

[ad_1]

This problem is to apply Roult’s Law.

Roult’s Law states that the vapor pressure, p, of a solution of a non-volatile solute is equal to the vapor pressure of the pure solvent, Po solv, times the mole fraction of the solvent, Xsolv

p = Xsolv * Po sol

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

Answer: 30.6 torr

[ad_2]

Categories
Assignment Help

Impure benzoic acid was dissolved in hot water. the container of solution was placed in an ice-water bath instead of being allowed cooling slowly .what will be the result of cooling the solution in this manner

[ad_1]

This problem is to apply Roult’s Law.

Roult’s Law states that the vapor pressure, p, of a solution of a non-volatile solute is equal to the vapor pressure of the pure solvent, Po solv, times the mole fraction of the solvent, Xsolv

p = Xsolv * Po sol

X solv = number of moles of solvent / number of moles of solution

The solvent is water and the solute (not volatile) is glycerin.

Number of moles = mass in grams / molar mass

mass of water = 132 ml * 1 g/ml = 132 g

molar mass of water = 18 g/mol

=> number of moles of water = 132 g / 18 g/mol = 7.33333 mol

mass of glycerin = 27.2 g

molar mass of glycerin:, C3H8O3: 3 * 12 g/mol + 8 * 1 g/mol + 3*16 g/mol = 92 g/mol

number of moles of glycerin = 27.2g / 92 g/mol = 0.29565

total number of moles = 7.33333 moles + 0.29565 moles = 7.62898 moles

=> X solv = 7.33333 / 7.62898 = 0.96125

=> p = 0.96125 * 31.8 torr ≈ 30.57 torr ≈ 30.6 torr.

Answer: 30.6 torr

[ad_2]

Categories
Assignment Help

The solubility of sugar is 203.9 g/100 g H2O at 20°C. To make candy from crystallized sugar, 300.0 g of sucrose is dissolved in 75 g of water at 100°C. To the nearest gram, how much sugar crystallized out of the saturated solution when it cooled to 20 C?

[ad_1]

Answer : The amount of sugar crystallized out of the saturated solution when it cooled to 20^oC is, 147 grams.

Solution :

First we have to calculate the amount of sugar remains in the solution.

As, 100 gram of water contains 203.9 gram of sugar

So, 75 gram of water contains frac{203.9g}{100g}times 75g=152.9g of sugar

Now we have to calculate the amount of sugar crystallized out of the saturated solution.

text{The amount of sugar crystallized out}=text{Initial sugar}-text{Remaining in the solution}

text{The amount of sugar crystallized out}=300g-152.9g=147.1=147g

Therefore, the amount of sugar crystallized out of the saturated solution when it cooled to 20^oC is, 147 grams.

[ad_2]

Categories
Assignment Help

An experiment is designed to determine if the amount of sugar in a drink affects the likelihood that bees will be attracted to it. Sample A is 100 mL of pure water. Sample B is 100 mL of water with 1 gram of sugar dissolved in it. Sample C is 100 mL of water with 2 grams of sugar dissolved in it. All samples are placed on a picnic table. One observer is assigned to each drink. The observers count the number of bees that visit the drink during a 15-minute interval.

[ad_1]

Answer: c. Count the number of tomatoes that are produced by a tomato plant that is grown in clay soil, and compare it to the number of tomatoes that are produced by a tomato plant that is grown in sandy soil.

Explanation:

Scientific design is like a detail procedure for conducting the research. It includes a typical hypothesis or a scientific inquiry which is required to be proved. It includes a method of survey or data collection, and an experimental procedure.  

An independent variable can be changed or manipulated by the experimenter the impact of which can be observed on the dependent variable. The dependent variable is the outcome of the experiment.  

According to the given situation, soil type is the independent variable and the the yield of tomatoes should be the dependent variable. As the type of soil chosen will directly influence the yield of tomatoes.

On the basis of the above information, c. Count the number of tomatoes that are produced by a tomato plant that is grown in clay soil, and compare it to the number of tomatoes that are produced by a tomato plant that is grown in sandy soil. is the correct option.

[ad_2]

Categories
Assignment Help

Zn(s) + 2HCl(aq) mc029-1.jpg H2(g) + ZnCl2(aq) Which product is a substance that is dissolved in solution?

[ad_1]

Answer:

B; Some of the products formed  from the experiment escaped to the surroundings as gas.

Explanation:

We are given that Brie is Studying the law of conservation of mass at school , so she decides to test it.First , she measures and records the mass of 1 teaspoon of baking soda and 1 table spoon of vinegar .

We have to find best explains the mass of reactants in Brie’s experiment was greater than the mass of products.

Then , she combines the two substances and observes

The chemical formula of baking soda is NaHCO_3(Base)

The chemical formula of vinegar is  CH_3COOH (Acid)

NaHCO_3+CH_3COOHrightarrow CH_3COONa+CO_2+H__2O

 CH_3COONa= Sodium Acetate (Salt)

H_2O=Liquid=Water

CO_2=Carbon dioxide=Gas

When we combine 1 teaspoon sodium bicarbonate and 1 teaspoon vinegar

Then sodium acetate salt , water and gas carbon dioxide are formed.

she. notices that mixture bubbles of   carbon dioxide. vigorously .After the mixture stops bubbling, she measures and records the mass of it .

When she examine her data , she notices that the mass of mixture is less than the mass of the vinegar and baking soda added together because carbon dioxide is a gas which escape into surrounding  . Therefore, the mass of product decreases due to escaping of gas.

Brie, is confused because it appears as if mass not conserved.

The mass of reactants is greater than the mass of products due to escaping  of gas into surrounding. So , the mass is not conserved in Brie’s experiment.

Answer:B; Some of the products formed  from the experiment escaped to the surroundings as gas.

[ad_2]

Categories
Assignment Help

How does low body temperature affect the blood's ability to carry dissolved oxygen

[ad_1]

How does low body temperature affect the blood’s ability to carry dissolved oxygen

[ad_2]

Categories
Assignment Help

SCIENCE HELP PLEASE!!!! Nutrient pollution causes algal blooms and fish kills. Question 2 options: True False Save Question 3 (1 point) Question 3 Unsaved In normal ecosystem low nutrient levels keep algae in check. Question 3 options: True False Save Question 4 (2 points) Question 4 Unsaved Which of the following contributes to excess nutrients entering the bay? Question 4 options: Sewage run-off Not recycling Agricultural run-off Air pollution Save Question 5 (2 points) Question 5 Unsaved In order to get Phase 2 to turn blue (like we saw in Phase 1), did we need more or less drops of Reagent D than what we used in Phase 1? Question 5 options: More Less Save Question 6 (2 points) Question 6 Unsaved Which stage of of the experiment had the MOST dissolved oxygen in the water? Question 6 options: Phase 1 Phase 2 Phase 3

[ad_1]

SCIENCE HELP PLEASE!!!! Nutrient pollution causes algal blooms and fish kills. Question 2 options: True False Save Question 3 (1 point) Question 3 Unsaved In normal ecosystem low nutrient levels keep algae in check. Question 3 options: True False Save Question 4 (2 points) Question 4 Unsaved Which of the following contributes to excess nutrients entering the bay? Question 4 options: Sewage run-off Not recycling Agricultural run-off Air pollution Save Question 5 (2 points) Question 5 Unsaved In order to get Phase 2 to turn blue (like we saw in Phase 1), did we need more or less drops of Reagent D than what we used in Phase 1? Question 5 options: More Less Save Question 6 (2 points) Question 6 Unsaved Which stage of of the experiment had the MOST dissolved oxygen in the water? Question 6 options: Phase 1 Phase 2 Phase 3

[ad_2]

Categories
Assignment Help

What is the molarity of 4 moles of C6H12O6 dissolved in 16 L of solution?

[ad_1]

What is the molarity of 4 moles of C6H12O6 dissolved in 16 L of solution?

[ad_2]

Categories
Assignment Help

Kylie has two glasses with equal volumes of pure water. She adds 40 g of sugar to one of the glasses of water and 40 g of salt to the other. When sugar is dissolved in water, it does not change the number of ions present. When salt is dissolved in water, however, the number of ions significantly increases. Which of the following is true about the electrical conductivity of Kylie's two solutions? A)The solution of sugar water will have a higher conductivity than the solution of salt water. B) Pure water will have a higher conductivity than both the sugar water and the salt water. C) The solution of salt water will have a higher conductivity than the solution of sugar water. D) The solution of salt water and the solution of sugar water will have the exact same conductivity.

[ad_1]

Kylie has two glasses with equal volumes of pure water. She adds 40 g of sugar to one of the glasses of water and 40 g of salt to the other. When sugar is dissolved in water, it does not change the number of ions present. When salt is dissolved in water, however, the number of ions significantly increases. Which of the following is true about the electrical conductivity of Kylie’s two solutions? A)The solution of sugar water will have a higher conductivity than the solution of salt water. B) Pure water will have a higher conductivity than both the sugar water and the salt water. C) The solution of salt water will have a higher conductivity than the solution of sugar water. D) The solution of salt water and the solution of sugar water will have the exact same conductivity.

[ad_2]