looking at the pure subtances :water,oxygen,copper, can you tell by looking at them if it is pure or not ? explain your answer using example...​

Answer:

The total change in enthalpy for the reaction is - 81533.6 J/mol

Explanation:

Given the data in the question;

Reaction;

HCl + NaOH → NaCl + H₂O

Where initial temperature is 21.2 °C and final temperature is 28.0 °C. Ccal is 1234.28 J

Moles of NaOH  = 50.mL × 1.00 M = 50.0 mmol = 0.0500 mol

Moles of HCl = 50.mL × 1.00 M = 50.0 mmol = 0.0500 mol

so, 0.0500 moles of H₂O produced

Volume of solution = 50.mL  +  50.mL  = 100.0 mL

Mass of solution m = volume × density = 100.0mL × 1.0 g/mL = 100 g

now ,

Heat energy of Solution q= (mass × specific heat capacity × temp Δ) + Cal

we know that; The specific heat of water(H₂O) is 4.18 J/g°C.

so we substitute

q_soln = (100g × 4.18 × ( 28.0 °C - 21.2 °C) ) + 1234.28

q_soln = 2842.4 + 1234.28

q_soln = 4076.68 J

Enthalpy change for the neutralization is ΔH[tex]_{neutralization}[/tex]

ΔH[tex]_{neutralization}[/tex] = -q_soln / mole of water produced

so we substitute

ΔH[tex]_{neutralization}[/tex] = -( 4076.68 J ) / 0.0500 mol  

ΔH[tex]_{neutralization}[/tex] = - 81533.6 J/mol

Therefore, the total change in enthalpy for the reaction is - 81533.6 J/mol

Explanation:

i believe this is right. my bad if its not

Answer:

The independent and dependent variable for the following are as follows:

a. Temperature and amount of dissolved oxygen

b. pH and SO2 solubility/amount

c. H2SO4 concentration and voltage output/performance of battery

Explanation:

In an experiment;

- Independent variable is the variable that the experimenter manipulates or changes in order to get a measurable response.

- Dependent variable is the variable that the experimenter measures based on its response to changes made to the independent variable.

A). In this experiment, a student is trying to investigate the amount of dissolved oxygen in a local pond in response to changes in temperature. Hence, the independent variable is the TEMPERATURE while the dependent variable is the AMOUNT OF DISSOLVED OXYGEN.

B). In this experiment, a wine producer would like to explore if pH affects the solubility of SO2 in the wine by measuring the amount of SO2 in the wine solution over a range of pH values. Hence, the independent variable is the pH while the dependent variable is the SO2 SOLUBILITY OR AMOUNT.

C). In this experiment, a researcher wishes to determine the optimal H2SO4 concentration for the best performance of the battery, as measured by the voltage output. Hence, the independent variable is the CONCENTRATION OF H2SO4 while the dependent variable is the VOLTAGE OUTPUT or PERFORMANCE of the battery.

Answer:

Explanation:

Molal freezing point depression constant of butanol Kf = 8.37⁰C /m

ΔTf = Kf x m , m is no of moles of solute per kg of solvent .

mol weight of butanol = 70 g

235.1 g of butanol = 235.1 / 70 = 3.3585 moles

3.3585 moles of butanol dissolved in 4.14 kg of water .

ΔTf = 8.37 x 3.3585 / 4.14

= 6.79⁰C

Depression in freezing point = 6.79

freezing point of solution = - 6.79⁰C .

Answer:

N(Au) = 1,20 × 10²²

Explanation:

1) n(Au) = m ÷ M = 4.60 g ÷ 197 g/mol = 0,02 mol

2) N(Au) = n(Au) × N(a) = 0,02 × 6.02*10²³ = 1,20 × 10²²

Answer:

11.7

Explanation:

The pH is the negative logarithm of the concentration of H+ ions. If the concentration is 2×10-¹² the the pH will be -log(2×10-¹²) which is 11.698 which can be round up to 11.7.

Answer:

particles

atoms

broken

isotope

conductors

electricity

element

combined

Answer:

the answer to this question is A H202

Answer:

Ionic Substance is....

Explanation:

In chemistry, an ionic compound is a chemical compound composed of ions held together by electrostatic forces termed ionic bonding. The compound is neutral overall, but consists of positively charged ions called cations and negatively charged ions called anions.

Answer:

96.09 g/mol

Explanation:

A higher density water will be obtained in lower temperature water.

Density is the fluid property that describes the amount of solutes that dissolves in a given volume of the fluid.

Density of a fluid is calculated by taking the ratio of mass to volume of the fluid.

[tex]\rho = \frac{m}{v}[/tex]

When the temperature of the water is low, more mass of the water is obtained while a high temperature evaporates the liquid.

Thus, a higher density water will be obtained in lower temperature water.

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Hello. Your question is missing data, which makes it difficult to answer it with exactness, but I will try to help you in the best possible way.

If the reaction absorbs energy it means that the reaction is endothermic. This is because endortemic reactions are those that absorb energy from the environment, as opposed to exothermic reactions that release energy into the environment.

In that case, if the reaction is absorbing energy, it is appropriate for the water bath temperature to drop.

Answer:

6.9 hours

Explanation:

In order to solve this problem we'll convert 837 km to miles (another option would be to convert 75 mi/hr to km/hr). To make said conversion we'll use the given conversion factor:

Finally we calculate the time required to travel said distance at a constant speed of 75 mi/hr:

The amount of time it would take to travel 837 km is equal to 7 hours.

Given the following data:

To determine the amount of time it would take to travel 837 km:

First of all, we would convert the value of the distance in kilometers to miles as follows:

Conversion:

1.61 km = 1 mile

837 km = X mile.

Cross-multiplying, we have:

[tex]X=\frac{837}{1.61}[/tex]

X = 519.88 miles.

Mathematically, time is given by this formula:

[tex]Time = \frac{distance}{speed}[/tex]

Substituting the given parameters into the formula, we have;

[tex]Time = \frac{519.88}{75}[/tex]

Time = 6.93 ≈ 7 hours.

Read more on time here: https://brainly.com/question/12199398

Answer:

Drycell and car battery

Explanation:

Is it only one answer because I think both of these are redox reactions.

Answer: BI

because of rection progress

Explanation:

Answer:

The steps involved in determining a Molecular Formula are: Find the mass of the empirical formula. Divide the molecular mass by the mass of the empirical formula. Multiply each subscript in the empirical formula by the answer.

Explanation:

Answer:

0.389 M

Explanation:

From the question given above, the following data were obtained:

Mass of CuCl₂ = 78.5 g

Volume of solution = 1.50 L

Molarity of CuCl₂ =?

Next, we shall determine number of mole in 78.5 g of CuCl₂. This can be obtained as follow:

Molar mass of CuCl₂ = 63.5 + (35.5×2)

= 63.5 + 71

= 134.5 g/mol

Mass of CuCl₂ = 78.5 g

Number of mole of CuCl₂ =?

Mole = mass / Molar mass

Number of mole of CuCl₂ = 78.5 / 134.5

Number of mole of CuCl₂ = 0.584 mole

Finally, we shall determine the molarity of the solution. This can be obtained as follow:

Number of mole of CuCl₂ = 0.584 mole

Volume of solution = 1.50 L

Molarity of CuCl₂ =?

Molarity = mole / Volume

Molarity of CuCl₂ = 0.584 / 1.50

Molarity of CuCl₂ = 0.389 M

The molarity of a solution that contains 78.5 g of copper(II) chloride in 1.50 L of solution is 0.389M.

The molarity of a solution can be calculated

From the question given above, the following data were obtained:

Next, we shall determine number of moles in 78.5g of CuCl₂. This can be obtained as follow:

Molar mass of CuCl₂ = 63.5 + (35.5×2)

= 63.5 + 71

= 134.5 g/mol

Mass of CuCl₂ = 78.5g

Number of mole of CuCl₂ = 78.5 / 134.5

Number of mole of CuCl₂ = 0.584 moles

The determine the molarity of the solution. This can be obtained as follow:

Molarity = mole / Volume

Molarity of CuCl₂ = 0.584 / 1.50

Molarity of CuCl₂ = 0.389M

Therefore, molarity of a solution that contains 78.5 g of copper(II) chloride in 1.50 L of solution is 0.389M.

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Answer:

0.263 mol

Explanation:

K2SO4 - potassium sulfate

Molar mass (K2SO4) = 2*39.0983 + 32.065 + 4*15.9994 =

= 174.2592≈174.26 g/mol

45.8 g * 1 mol/174.26 g = 0.263 mol

Answer:

MM = 225.11 g/mol

Explanation:

In this case, let's analyze the data.

We have a 15.2 mg of an unknown electrolyte in 150 mL of solution. The osmotic pressure is 8.44 Torr, and we want the molecular mass of the unknown.

The osmotic pressure can be calculated using the following expression:

π = CRT   (1)    

π: osmotic pressure (8.44 Torr * 1 atm / 760 Torr = 0.011 atm)

C: Concentration of the unknown in the solution

R: universal constant of gases (0.082 L atm / K mol)

T: temperature in Kelvin (25 + 273 = 298 K)

From this expression, we can either solve for C, and then use another expression to calculate the molecular mass, or we can just replace the expressions in the above formula, to get the direct molecular mass. In this case, we'll follow the second method.

Concentration or molarity of a substance can be calculated using:

C = moles / V  (2)

And moles can be calculated using this expression:

moles = m / MM   (3)

Replacing (3) in (2), and then in (1) we have:

C = m / MM * V

π = m * RT / MM * V   (4)

and now, we can solve for MM:

MM = mRT / π V  (5)

Now, we just need to replace the given data into the above expression to get the value of the molecular mass:

MM = (15.2 / 1000) * 0.082 * 298 / 0.011 * 0.150

Hope this helps

Answer: the electrostatic potential energy is -3.26 × 10⁻¹⁸ J

Explanation:

Given the data in the question;

I think the value of electrostatic potential energy of calcium sulfide CaS formed will be less(more negative) than KCl because the Ca2+ and S2- ions has more charge that is +2 and -2 respectively when compared to Kcl which has +1 and -1 charge.so it will be more negative.

radius = r[tex]_{ca+2}[/tex] + r[tex]_{s-2}[/tex] = 100 + 184 = 284 pm = 2.84 × 10⁻¹⁰ m

we know that; k = 2.31 × 10⁻²⁸ J

q1 = 2  ( charge on Ca⁺² )

q2 = -2( charge on S⁻²)

so

Ep = k × q1q2/r

so we substitute

Ep = 2.31 × 10⁻²⁸ × (+2×-2) / 2.84 × 10⁻¹⁰

Ep = (2.31 × 10⁻²⁸ × -4) / 2.84 × 10⁻¹⁰

Ep = -9.24 × 10⁻²⁸ / 2.84 × 10⁻¹⁰

Ep = -3.26 × 10⁻¹⁸ J

Therefore, the electrostatic potential energy is -3.26 × 10⁻¹⁸ J

Based on the data provided, the electrostatic potential energy is -3.26 × 10⁻¹⁸ J

The electrostatic potential energy is the work done in moving the charge from infinity to that point against the electric field.

The electrostatic potential energy between any two charges q1, q2 separated by distance r is derived from Coulomb’s law and mathematically given as:

where

From the data provided:

ionic radii of Ca2+ r1 = 100 pm

ionic radii of S2– = 184 pm.

Chargeon Ca2+ = +2

Charge on S2_ = -2

From the data above, it most likely that the value of electrostatic potential energy of calcium sulfide CaS formed will be less(more negative) than KCl because the Ca2+ and S2- ions has a greater charge of +2 and -2 respectively compared to Kcl which has +1 and -1 charge.

Calculating the electrostatic potential energy, Ep:

radius = r1 + r2 = 100 + 184 = 284 pm

r = 2.84 × 10⁻¹⁰ m

k = 2.31 × 10⁻²⁸ J

q1 = 2  ( charge on Ca⁺² )

q2 = -2( charge on S⁻²)

Then:

Ep = k × q1q2/r

Substituting the values above in the equation:

Ep = 2.31 × 10⁻²⁸ × (+2 ×-2) / 2.84 × 10⁻¹⁰

Ep = (2.31 × 10⁻²⁸ × -4) / 2.84 × 10⁻¹⁰

Ep = -9.24 × 10⁻²⁸ / 2.84 × 10⁻¹⁰

Ep = -3.26 × 10⁻¹⁸ J

Therefore, the electrostatic potential energy is -3.26 × 10⁻¹⁸ J.

Learn more about electrostatic potential energy at: https://brainly.com/question/24648428

Answer:

Oxygen

Explanation:

In photosynthesis, solar energy is harvested and converted to chemical energy in the form of glucose using water and carbon dioxide. Oxygen is released as a byproduct.

Answer:

the answer is a) oxygen

Explanation:

when plants are performing photosynthesis they take in carbon dioxide given out by humans and animals which is the balance of nature and give out oxygen. in this process sunlight and chlorophyll is also involved!!!!

I hope I cleared your doubt :)

Answer:

true

Explanation:

Prophase is the first stage in mitosis, occurring after the conclusion of the G2 portion of interphase. During prophase, the parent cell chromosomes which were duplicated during S phase condense and become thousands of times more compact than they were during interphase.

Answer:

Hello your question is poorly written hence i will give you a more general answer

answer :  The reason why it is desirable to use an excess of barium ion in the precipitation is to form the compound needed,

Explanation:

Natural Precipitation occurs when condensed atmospheric water vapor falls due to the gravitational pull exerted on it by the clouds. precipitation can be in various forms like ; rain , ice pellets and snow . e.t.c

Hence the reason why it is desirable to use an excess of barium ion in the precipitation is to form the compound needed,

Also in order to form the precipitation, we will also add excess of barium ion which will help form the required precipitate and also  filter out the mass of Sulphate.

Answer:

See Down

Explanation:

2Al2O3 = 4Al + 3O2 (Decomposition)

31.5/101.961g = 0.3089mol

(0.3089mol/2) * 4 = 0.61788 mole of Al

0.61788 mole * 6.022x10^23 atoms/mol = Your answer

Answer:

False

Explanation:

Groundwater and surface water have a relationship.

Groundwater is the water that is contained in a subsurface layer of an underlying soil/rock whereas surface water is that found in a lake, river or some other surface cavities.

However, when groundwater is discharged to surface water bodies, it is said to be surface water. Thus the statement asked is false.