pls help What are the benefits and limitations of scientific experiments and investigations?

Answer:

The limiting reactant is: H₂O

265.3 g of K₂Sn(OH)₆ are formed in the reaction.

Explanation:

The reaction is:

Sn(s) + 2KOH (aq) + 4H₂O(l)  → K₂Sn(OH)₆ (s) + 2H₂ (g)

The first step to solve is to determine the moles of each reactant:

We controlled that reaction is ballanced.

122 g . 1mol / 118.71g = 1.03 moles of Sn

134g . 1mol /56.1g = 2.39 moles of KOH

63.9 g .1mol /18g = 3.55 mol of water

Stoichiometry is 1:2:4.

Sn is the lowest reactant and water, the highest, but I can see, that water is the limiting.

1 mol of Sn needs 4 moles of H₂O to react

Then, 1.03 moles of Sn may react to (1.03 . 4)/1 = 4.12 moles.

We only have 3.55 moles. It's ok.

2 moles of KOH need 4 moles of H₂O to react

Then, 2.39 moles of KOH may react to (2.39 . 4) /2 = 4.78 moles.

We only have 3.55, there's no enough water.

So 4 moles of water can produce 1 mol of potassium hydroxystannate

Then, 3.55 moles of H₂O may produce (3.55 . 1)/4 = 0.8875 moles.

We convert moles to mass: 0.08875 mol . 298.91g /1mol =265.3g

Answer:

alpha particle needs to be added to the equation.

Explanation:

Given;

atomic mass of Americium = 241

atomic mass of neptunium = 237

The difference in atomic mass of the radioactive elements given is calculated as;

241 - 237 = 4

The particle with atomic mass of 4 is alpha particle usually represented with helium atom.

Am²⁴¹ -----> He⁴ + Np²³⁷

Thus, alpha particle needs to be added to the equation.

Answer:

4/2 HE

Explanation:

a p e x!

Answer: The mass of sodium acetate anhydrous required is 0.820 g

The mass of sodium acetate trihydrate required is 1.36 g

The mass of Iron (III) chloride required is 2.70 g

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]

where,

n = moles of solute

= volume of solution in ml

1. moles of =

Now put all the given values in the formula of molarity, we get

[tex]0.100=\frac{x\times 1000}{82.03\times 100.0}[/tex]

[tex]x=0.820g[/tex]

Therefore, the mass of sodium acetate anhydrous required is 0.820 g

2.   moles of [tex]CH_3COONa.3H_2O[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{xg}{136.08g/mol}[/tex]

Now put all the given values in the formula of molarity, we get

[tex]0.100=\frac{x\times 1000}{136.08\times 100.0}[/tex]

[tex]x=1.36[/tex]

Therefore, the mass of sodium acetate trihydrate required is 1.36 g

3. moles of [tex]FeCl_3.6H_2O[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{xg}{g/mol}[/tex]

Now put all the given values in the formula of molarity, we get

[tex]0.100=\frac{x\times 1000}{270.33\times 100.0}[/tex]

[tex]x=2.70g[/tex]

Therefore, the mass of Iron (III) chloride required is 2.70 g

Answer:

Calcium flouride?

Explanation:

Quite self explanatory

Answer:

4.5M

Explanation:

The solution was diluted from 2.0L to 3.0L, the dilution factor was:

3.0L / 2.0L = 1.5.

That means the solution was diluted 1.5 times.

As the final molarity of the diluted solution is 3.0M, the initial molarity of the solution was:

3.0M * 1.5 =

Answer:

A.

Explanation:

In an endothermic reaction heat is applied.

In an endothermic process, heat is transferred from the surroundings to the system.

What are endothermic and exothermic processes?

An exothermic process is one that gives off heat. This heat is transferred to the surroundings. An endothermic process is one in which heat has to be supplied to the system from the surroundings.

The endothermic process is a term that describes a reaction where the system absorbs the energy from its surrounding in the form of heat. A few examples of the endothermic process are photosynthesis, evaporating liquids, melting ice, etc.

The exothermic reaction is the opposite of an endothermic reaction. It releases energy by light or heat to its surrounding. A few examples are neutralization, burning of a substance, reactions of fuels, etc.

Hence, option A is the correct answer.

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Answer:

false

Explanation:

All the members of one species in a particular area are referred to as a population. All the different populations that live together in an area make up a community. The community of organisms that live in a particular area, along with their nonliving surroundings, make up an ecosystem.

Answer:

Permafrost is any part of the ground that remains completely frozen or colder

Answer:

HCO₂

Explanation:

From the information given:

The mass of the elements are:

Carbon C = 26.7 g;     Hydrogen H = 2.24 g     Oxygen O = 71.1 g

To determine the empirical formula;

First thing is to find the numbers of moles of each atom.

For Carbon:

[tex]=26.7 \ g\times \dfrac{1 \ mol }{12.01 \ g} \\ \\ =2.22 \ mol \ of \ Carbon[/tex]

For Hydrogen:

[tex]=2.24 \ g\times \dfrac{1 \ mol }{1.008 \ g} \\ \\ =2.22 \ mol \ of \ Hydrogen[/tex]

For Oxygen:

[tex]=71.1 \ g\times \dfrac{1 \ mol }{1.008 \ g} \\ \\ =4.44 \ mol \ of \ oxygen[/tex]

Now; we use the smallest no of moles to divide the respective moles from above.

For carbon:

[tex]\dfrac{2.22 \ mol \ of \ carbon}{2.22} =1 \ mol \ of \ carbon[/tex]

For Hydrogen:

[tex]\dfrac{2.22 \ mol \ of \ carbon}{2.22} =1 \ mol \ of \ hydrogen[/tex]

For Oxygen:

[tex]\dfrac{4.44 \ mol \ of \ Oxygen}{2.22} =2 \ mol \ of \ oxygen[/tex]

Thus, the empirical formula is HCO₂

Answer:

The number of protons in one atom of an element determines the atom's identity, and the number of electrons determines its electrical charge. The atomic number tells you the number of protons in one atom of an element. It also tells you the number of electrons in a neutral atom of that element.

Explanation:

Answer:

Convergent Plate Boundaries

Explanation:

I hope this helps :)

Answer:

Lancelet

Explanation:

This is because a Lancelet is a small elongated marine invertebrate that lacks all of the physiological and biological traits of a leopard

Answer:

The Lewis structure for the sulfate ion consists of a central sulfur atom with four single bonds to oxygen atoms. This yields the expected total of 32 electrons. Since the sulfur atom started with six valence electrons, two of the S-O bonds are coordinate covalent.

Explanation:

Then that means it has both.

Answer:

Explanation:

It is 11

Answer:

C). Electronegativity.

Explanation:

'Electronegativity' is described as the tendency or a measure of the ability of an atom or molecule to attract electrons that leads to the formation of chemical bonds. It is denoted by 'χ', a Greek letter. The elements like Fluorine having a very high rate of electronegativity, its atom would attract the electrons more strongly while the elements with lesser electronegativity like Cesium would possess a lesser tendency to attract electrons towards it in order to form a bond. Thus, option C is the correct answer.

Answer:

14

Explanation:

Step 1: Calculate the moles corresponding to 25 g of Ba(OH)₂

The molar mass of Ba(OH)₂ is 171.34 g/mol.

25 g × 1 mol/171.34 g = 0.15 mol

Step 2: Calculate the molar concentration of Ba(OH)₂

Molarity is equal to the moles of solute divided by the liters of solution.

[Ba(OH)₂] = 0.15 mol/0.250 L = 0.60 M

Step 3: Calculate the molar concentration of OH⁻

Ba(OH)₂ is a strong base according to the following equation.

Ba(OH)₂ ⇒ Ba²⁺ + 2 OH⁻

The molar ratio of Ba(OH)₂ to OH⁻ is 1:2. The molar concentration of OH⁻ is 2/1 × 0.60 M = 1.2 M.

Step 4: Calculate the concentration of H⁺

We will use the ionic product of water expression.

Kw = 1.0 × 10⁻¹⁴ = [H⁺] × [OH⁻]

[H⁺] = 1.0 × 10⁻¹⁴/[OH⁻] = 1.0 × 10⁻¹⁴/1.2 = 8.3 × 10⁻¹⁵ M

Step 5: Calculate the pH of the solution

We will use the definition of pH.

pH = -log [H⁺] = -log 8.3 × 10⁻¹⁵ = 14

Answer:

Attached picture.

Explanation:

(1) Ksp equals the product of [Co 2+][CO3 2-]. CoCO3 is excluded from the equilibrium expression because it is a pure solid. The mole ratio of Co 2+ and CO3 2- is 1:1 so their molar solubilities are the same.

(2) There is an initial concentration of 0.10 M Co 2+ so write that in the "I" row for Co 2+ on the ICE table. When you find the zeros of the quadratic when solving for "s", take the positive value rather than the negative value because concentration cannot be negative.

(3) Extra products will cause the equilibrium to consume products and form reactants. So the reverse reaction will occur faster than the forward reaction. More products mean an increased Q value compared to K, since the numerator of [tex]K = \frac{[products]}{[reactants]}[/tex] increases.

Answer:

THE ANSWER IS 1.167L

Explanation:

Answer: 1672 Joules

Explanation:

The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.

[tex]Q=m\times c\times \Delta T[/tex]

Q = Heat absorbed by water = ?  

c = heat capacity of water = [tex]4.18 J/g^0C[/tex]

Initial temperature of the water = [tex]T_i[/tex] = [tex]27^0C[/tex]

Final temperature of the water  = [tex]T_f[/tex]  = [tex]35^0C[/tex]

Change in temperature ,[tex]\Delta T=T_f-T_i=(35.0-27.0)^0C=8.0^0C[/tex]

Putting in the values, we get:

[tex]Q=50.0g\times 4.18J/g^0C\times 8.0^0C=1672J[/tex]

As heat absorbed by water is equal to the heat released by metal, the Joules of heat transferred are 1672 Joules

Answer:

0 587 mL

Explanation:

First we convert 180 grams of HCl into moles, using its molar mass:

Now we can use the number of moles and the given concentration to calculate the required volume, applying the definition of molarity:

Finally we convert liters into milliliters:

The closest answer is option C, 587 mL.

The volume needed to make an 8.40 M solution of HCl is 0.587 ml.

The correct option is C.

HCl is a strong acid. It is present in our stomach to help in digesting food.

Step1: covert 180 grams into moles

Molar mass of HCl is 36.46 g

[tex]\dfrac{180 g}{36.46 g/mol } = 4.94\; mol\; HCl[/tex]

Step2: calculate the molarity

[tex]\rm Molality = \dfrac{mol}{L}\\\\\rm L = \dfrac{4.94 mol }{8.40 M} = 0.588 L\\[/tex]

Covert the liters into ml

[tex]\dfrac{0.588 L}{1000} = 588 mL[/tex]

Thus, the volume of the solution is 588 ml., nearest is option C, 587 ml.

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Answer:

C.

Explanation:

Answer:

[tex]\boxed {\boxed {\sf \frac {1}{3} \ mol \ Al_2O_3 \approx 0.34 \ mol \ Al_2O_3}}[/tex]

Explanation:

We will use stoichiometry to solve this problem. The reaction given has a formula of

[tex]4Al+3O_2 \rightarrow 2Al_2O_3[/tex]

The coefficients tell us the number of moles necessary for the reaction.

The reaction requires 3 moles of oxygen to produce 2 moles of aluminum oxide. We can make a ratio.

[tex]\frac {3 \ mol \ O_2}{ 2\ mol \ Al_2O_3}}[/tex]

Since we are doing the reaction with 0.5 moles of oxygen, we multiply the ratio by that number.

[tex]0.5 \ mol \ O_2 *\frac {3 \ mol \ O_2}{ 2 \ mol \ Al_2O_3}}[/tex]

Flip the ratio so the moles of oxygen cancel each other out.

[tex]0.5 \ mol \ O_2 *\frac {2 \ mol \ Al_2O_3}{ 3 \ mol \ O_2}}[/tex]

[tex]0.5 *\frac {2 \ mol \ Al_2O_3}{ 3 }[/tex]

[tex]\frac {1 \ mol \ Al_2O_3}{ 3 }[/tex]

[tex]\frac {1}{3} \ mol \ Al_2O_3 = 0.33333 \ mol \ Al_2O_3 \approx 0.34 \ mol \ Al_2O_3[/tex]

0.5 moles of oxygen produces 1/3 or approximately 0.34 moles of aluminum oxide.

Answer:

894 deg K

Explanation:

The computation is shown below:

Given that

V1 denotes the initial volume of gas = 2.00 L  

T1 denotes the initial temperature of gas = 25 + 273 = 298 K  

V2 denotes the final volume of gas  = 6.00 L  

T2 = ?

Based on the above information

Here we assume that the pressure is remain constant,

So,  

V1 ÷ T1 = V2 ÷ T2  

T2 = T1 × V2 ÷ V1

= (298)(6) ÷ (2)

= 894 deg K

Answer:

a)567mg

b)0.567 grams

Explanation:

There are 7 days in a week, so we multiply the number of weeks by the number of daily dosage.

81mg*7=567mg

1 gram is 1000 mg

we divide 567 by 1000 to get the value in grams

The statement which is  given below describe a homogeneous catalyst.

"It is in the same phase as the reactants"

The catalyst which have similar phase to the reactant of the reaction is called homogeneous catalyst.

Mostly in  homogeneous catalyst, catalyst present in liquid form.

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The correct answer is solution B!