Calculate the specific heat in J/(g·ºC) of an unknown substance if a 2.50-g sample releases 12.0 cal as its temperature changes from 25.0ºC to 20.0ºC. _________J/(g·°C)

Answers

Answer 1

Answer:

[tex]\fbox{c = - 4.01 \: joule/g°C}[/tex]

Step by step explanation:

Given:

Mass of given sample (m) = 2.50 g

Initial temperature (T1) = 25°C

Final temperature (T2) = 20°C

Heat Energy Q = 12 cal

To find:

[tex]Specific \: Heat \: c = \: ?[/tex]

Solution:

We know that,

Specific heat of any substance is directly proportional to the mass and change in temperature.

Represented by equation,

[tex]Q = mc \triangle T[/tex]

Where,

Q = Heat Energy

m = mass of given sample

c = specific heat

∆T = change in temperature

Substituting corresponding values,

[tex]Q = mc \triangle T \\ 12 = 2.5\times c \times (20-25) \\ c = \frac{12}{2.5 \times ( - 5)} \\ c = - 0.96 \: cal/g°C \\ [/tex]

We also know that,

[tex]1 \: cal = 4.184 \: joules[/tex]

multiplying above answer by 4.184,

[tex]c = - 0.96 \times 4.184 \\ \fbox{c = - 4.01 \: joule/g°C}[/tex]

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Related Questions

The correct IUPAC name for 2-isopropylbutane is: a) 2-ethylpentane b) 2,3-dimethylpentane c) 2-methylhexane d) 3-methylhexane

Answers

Answer:

a

Explanation:

On drawing the structure, the most Carbon atoms in a row is 5

⇒ pentane

The remaining two carbon atoms are connected to the 2nd carbon atom

2-ethyl

IUPAC name is :

2-ethyl + pentane2-ethylpentane

- If you have bottle filled with Sulfur Hexafluoride and there are 1.00 L of the liquid with a density of 1.60 g/mL, how many moles of the liquid are present?

Answers

Answer:

About 11.0 moles.

Explanation:

We are given a bottle filled with 1.00 L of sulfur hexafluoride (SF₆) and we want to determine the number of moles of the liquid that is present.

First, determine its mass with the given density:

[tex]\displaystyle \begin{aligned}\rho & = \frac{m}{V} \\ \\ m & = \rho V \\ \\ & = \left(\frac{1.60\text{ g}}{\text{mL}}\right)(1.00\text{ L})\left(\frac{1000\text{ mL}}{1\text{ L}}\right) \\ \\ & = 1.60\times 10^3 \text{ g}\end{aligned}[/tex]

The molecular weight of SF₆ is 146.07 g/mol. Hence:

[tex]\displaystyle 1.60\times 10^3\text{ g SF$_6$} \cdot \frac{1\text{ mol SF$_6$}}{146.07\text{ g SF$_6$}} = 11.0\text{ mol SF$_6$}[/tex]

Therefore, about 11.0 moles of sulfur hexafluoride is present.

Decomposition of hydrogen peroxide: 2H2O2 --> O2(g) + 2H2O(l) How many molecules of water are produced from the decomposition of 3.4g of hydrogen peroxide, H2O2?

Answers

Answer:

Explanation:

You have the equation. Now change the 3.4 g H2 to moles. moles = grams/molar mass

3.4 g/2.016 = 1.686 moles.

Now using the coefficients in the balanced equation, convert moles H2O2 to moles H2O.

1.686 moles H2 x (2 moles H2O/2 moles H2O2) = 1.686 x (2/2) = 1.686 x (1/1) = 1.686 moles H2O.

Now you know that 1 mole of water is composed of 6.022 x 10^23 molecules. So

1.686 moles H2O x (6.022 x 10^23 molecules H2O/1 mole H2O) = ?? molecules.

2C6H6 + 1502 →12CO2 + 6H20

Calculate the number of moles of C6H6 needed to produce 50.0g of water.
Show steps

Answers

Answer:

.926 moles

Explanation:

Rounding :

H2 0 = 18 gm/mole

   50 gm would then be   50 / 18 = 2.7777 moles of water

every two moles of 2 C6H6   produces   6 moles of water

   2.7777/6  * 2 = .926 moles

What are two relatively unique physical properties of water? What impact do these properties have on life on Earth?

Answers

Answer:

Polar molecule. A neutral, or uncharged molecule that has an asymmetric internal distribution of charge, leading to partially positive and partially negative regions

Cohesion The attraction of molecules for other molecules of the same kind

Adhesion The attraction of molecules for other molecules of a different kind

Density The mass per unit volume of a substance

Specific heat capacity The amount of heat needed to raise the temperature of one gram of a substance by one degree Celsius

Heat of vaporization The amount of energy needed to change one gram of a liquid substance to a gas at constant temperature

Polar substance. a molecule that is neutral or uncharged but has an asymmetric internal charge distribution that produces both positive and negative regions.

What are Physical properties ?

Cohesion molecules' attraction to other molecules of the same sort. Adhesion the pull of certain molecules toward others of a different type

Density a substance's mass per unit volume particular heat capacity The amount of heat required to increase a substance's temperature by one degree Celsius in one gram

Vaporization-related heat energy required to convert one gram of a liquid material into a gas at a fixed temperature.

Therefore, Polar substance. a molecule that is neutral or uncharged but has an asymmetric internal charge distribution that produces both positive and negative regions.

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How many grams of aluminum will be deposited by 0.1F? (Al=27) a.0.3g b. 0.9. c. 9.0g. d. 2.7g

Answers

Based on the charge on the aluminium ion, 0.9 g of aluminium are deposited by 0.1 F of electricity.

What is electrolysis?

Electrolysis is the decomposition of a substance known as an electrolyte when electric current is passed through it.

The mass and hence moles an electrolyte deposited when current is passed through it depends on the charge on the ion.

Aluminium ion has a charge of +3 and requires 3F of electricity to deposit 1 mole or 27 g of aluminium

0.1 F will discharge = 0.1/3 × 27 g of aluminium

mass of aluminium deposited = 0.9 g of aluminium.

Therefore, 0.9 g of aluminium are deposited by 0.1 F of electricity.

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Which of the following UV rays has the highest energy that damages your skin the most?

A. UVA

B. UVB

C. X-ray

D. Infrared (IR)

Answers

The answer is b) UVB

A sample of methane gas contains 3.62x10^29 atoms of hydrogen. What is the mass of the sample?

Answers

The mass of the sample to methane that contains 3.62×10²⁹ atoms of hydrogen is 4810631.24 g

Avogadro's hypothesis

6.02×10²³ atoms  = 1 mole of Hydrogen

How to determine the mass of Hydrogen

1 mole of Hydrogen = 2 g

Thus,

6.02×10²³ atoms  = 2 g of Hydrogen

Therefore,

3.62×10²⁹ atoms =  (3.62×10²⁹ × 2) / 6.02×10²³

3.62×10²⁹ atoms = 1202657.81 g of Hydrogen

How to determine the mass of methane 1 mole of methane, CH₄ = 12 + (4×1) = 16 gMass of H in 16 g of CH₄ = 4 × 1 = 4 g

Thus,

4 g of Hydrogen is present in 16 g of methane.

Therefore,

1202657.81 g of Hydrogen will be present in = (1202657.81 × 16) / 4 = 4810631.24 g of methane

Thus, we can conclude that the mass of the sample of methane is 4810631.24 g

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If you were to classify a newly discovered animal, what would you want to know first?
Does it live on land or in the sea?
Does it have a backbone?
Does it have hair?
Does it have vascular tissue?

Answers

Answer:

A

Does it live on land or sea.

Answer:

C:

I would check that does it have hair or not because hair provides info about the DNA which can help me if that specific animal has evolved from DNA of any other animal..

Hope it helped you.

When .080 moles of propane burn at STP, what volume of carbon dioxide is produced?
The answer is 5.4 L (I NEED THE STEPS)

Answers

Taking into account the reaction stoichiometry and the definition of STP, 5.4 L of carbon dioxide is produced.

Reaction stoichiometry

In first place, the balanced reaction is:

C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

C₃H₈: 1 mole O₂: 5 moles CO₂: 3 moles H₂O: 4 moles

Moles of CO₂ formed

The following rule of three can be applied: if by reaction stoichiometry 1 mole of C₃H₈ form 3 moles of CO₂, 0.080 moles of C₃H₈ form how many moles of CO₂?

[tex]amount of moles of CO_{2} =\frac{0.080 moles of C_{3} H_{8}x3 moles of CO_{2} }{1 mole of C_{3} H_{8} }[/tex]

amount of moles of CO₂= 0.24 moles

Definition of STP condition

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.

Volume of CO₂ produced

You can apply the following rule of three: If by definition of STP 1 mole of CO₂ occupies 22.4 L, 0.24 moles of CO₂ how much volume does it occupy?

[tex]volume of CO_{2} =\frac{0.24 molesx22.4 L}{1 mole}[/tex]

volume of CO₂= 5.376 L ≅ 5.4 L

Finally, 5.4 L of carbon dioxide is produced.

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the reaction stoichiometry:

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STP conditions:

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what mass of water must be added to 0.50 mol of glucose to make a solution of 25 percent by mass? the molar mass of glucose is 180 g/mol. SHOW WORK PLSS.

Answers

Answer:

270 g of water

Explanation:

pls help me with this

Answers

Answer:

silver

5/20

=0.25.................

Answer:

C

Explanation:

Aluminum density = 0.5

Iron density = 2

Gold density = 1

Silver density = 0.25

The smallest value is 0.25 hence silver has less density.

what is the empirical formula of a cpd containing 60.0%of sulfur 40.0% oxygen by mass​

Answers

Answer:

n S = 60 32 = 1.875 , n_S=\tfrac{60}{32}=1.875, nS=3260=1.875, n O = 40 16 = 2.5.

Explanation:

When .080 moles of propane burn at STP, what volume of carbon dioxide is produced?
The answer is 5.4 L (I NEED THE STEPS)

Answers

The volume of carbon dioxide produced is : 5.4 L

Given data:

moles of propane = 0.080 moles

Determine the volume of Carbon dioxide produced

The chemical reaction

C₃H₈  + 5O₂  ---- > 3CO₂ + 4H₂O

From the reaction

I mole of C₃H₈ = 3CO₂

0.080 moles of C₃H₈ =  3 * 0.080 = 0.24

Applying the equation below to determine the volume of CO₂

Pv = nRT

    = 0.24 * R * T

v = ( 0.24 * 8.314 * 273 ) / 1 atm

  = 544.7 ml = 5.4 L

Hence we can conclude that The volume of carbon dioxide produced is : 5.4 L

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what does rows represent on the periodic table

Answers

Answer:

Rows on the periodic table represents a period, which is the number of energy levels or rings. It is the last shell which valence electrons are on.

For example the first row waas Hydrogen and Helium which each have one  energy level.

The esecond row has Carbon and Oxygen which has two energy level.

The third row has Sodium which has three energy levels and so on.

Which of the following is not an example of a modified silicate?

Ceramics

Glass

Cement

Quartz

Answers

Quartz is not regarded as an example of a modified silicate.

What is Quartz?

This is defined as a hard, crystalline mineral composed of silica with a tetrahedral shape. Silica is also referred to as Silicon dioxide(SiO₂).

This type of mineral is a naturally occurring crystal and isn't a modified silicate but the rest can be modified using their respective constituents thereby making option D the most appropriate choice.

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Becquerel placed photographic paper in a drawer with some radioactive rocks and discovered that the amount of exposure on the paper was proportional to the amount of uranium that was present in the rocks. True False

Answers

Becquerel  did not discover that the amount of exposure on the paper was proportional to the amount of uranium that was present in the rocks

What is radioactivity?

The phenomenon of radioactivity was discovered by the French scientist Henri Becquerel in 1896 when he placed photographic paper in a drawer with some radioactive rocks.

We have to note that Becquerel did not discover that the amount of exposure on the paper was proportional to the amount of uranium that was present in the rocks hence the stetement is false.

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At 25°C the vapour pressure of pure pentane is 511 torr and that of hexane is 150. torr.
What is the mole fraction of pentane in a pentane-hexane solution that has a vapour pressure of 383 torr at 25°C?

ANSWER IS 6.45×10-1

QUESTION: What is the mole fraction of hexane in the vapour that is in equilibrium with this solution?
(Assume ideal gas behaviour.)

Answers

Based on the vapor pressure of the pure substances, the mole fraction of pentane is 0.45 and mole fraction of hexane at equilibrium is 0.60.

What is vapor pressure of a liquid?

Vapor pressure of of a liquid is the pressure that is excreted on the walls of a sealed vessel by the molecules of the liquid that have been converted to gaseous phase.

TO determine the mole fraction of pentane in the solution, we use the vapor pressure of the pure substances.

Let the mole fraction of pentane in the mixture be X.

The mole fraction of hexane will be 1 - X

The vapor pressure of the solution = (mole fraction of pentane × vapor pressure of pentane) + (mole fraction of hexane × vapor pressure of hexane)

Vapor pressure of solution = 383 torr

(mole fraction of pentane × vapor pressure of pentane) + (mole fraction of hexane × vapor pressure of hexane) = 383 torr

X × 511 + (1 - X) × 150 = 383

511X - 150X + 150 = 383

511X = 233

X = 0.45

Also , at equilibrium, the vapor pressure of pentane = 0.45 × 511 = 230 torr

mole fraction of hexane in the vapor that is in equilibrium with this solution = 230/383

mole fraction of hexane at equilibrium = 0.60

Therefore, the mole fraction of pentane is 0.45 and mole fraction of hexane at equilibrium is 0.60.

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There are 7 named classes of hazardous materials.
O True
O False

Answers

False, there are 9 named classes of hazardous materials.

What are hazardous materials?

Hazardous materials are substances or chemicals that pose a health hazard, a physical hazard, or harm to the environment.

There are 9 hazardous substances symbols you need to know: flammable, oxidising, explosives, gas under pressure, toxic, serious health hazard, health hazard, corrosive and environmental hazard.

Hence, the statement is false.

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I need help it’s calculating ph

Answers

1. pH = -log[H3O+]
= -log(1.0x10^-1)
= 1
2. The pH of 1 is acidic.

What state of matter has the most kinetic energy?
A gas
B liquid
C solid

Answers

Answer:

gaseous state.

Explanation:

that's the answer

What mass of water is in a calorimeter where 225.0 J of heat are
transferred to the water from a heated piece of metal and the
temperature of the water is increased by 4.00°C?

Answers

Answer:

22.25 °C

Explanation:

Determine the final temperature when a 25.0 g piece of iron at 85.0 °C is placed into 75.0 grams of water at 20.0 °C.

2. Which substance has definite volume and weight, but not a definite
shape?
B
A. ice
wood
C. gasoline
D. steam

Answers

Answer:

A solid has definite volume and shape, a liquid has a definite volume but no definite shape, and a gas has neither a definite volume nor shape. The change from solid to liquid usually does not significantly change the volume of a substance

Explanation:

no explanation

PROBLEM SETS: %BY MASS, % BY VOLUME, MOLARITY, MOLALITY (show your solution)
1. What is the molarity of a solution in which 0.850 grams of ammonium nitrate are dissolved in 345 mL of solution?
2. Calculate the molality of a solution of 13.5g of KF dissolved in 250. g of water.
3. Calculate the molality of a solution containing 16.5 g of dissolved naphthalene (C10H8) in 54.3 g benzene (C6H6).
4. What is the mass percent of each component in the mixture formed by adding 12 g of calcium sulfate, 18 g of sodium nitrate, and 25 g of potassium chloride to 500 g of water?
5. A solution is made by dissolving 125 g of sodium chloride in 1.5 kg of water. What is the percent by mass?
6. What is the percent by volume of a solution formed by added 15 L of acetone to 28 L of water?

Answers

The concentration of a substance can be expressed using molarity, molality or percent.

What is concentration?

The term concentration has to do with the amount of substance present in solution. Now let us solve the problems individually;

a) Number of moles =  0.850 grams/80 g/mol = 0.011 moles

molarity = 0.011 moles/345 * 10^-3 L = 0.032 M

b) Number of moles =  13.5g /58 g/mol = 0.23 moles

molality = 0.23 moles/250 * 10^-3 Kg = 0.92 m

c) Number of  moles = 16.5 g/128 g/mol = 0.13 moles

molality = 0.13 moles/54.3  * 10^-3 Kg =2.39 m

d) Total mass present =  12 g +  18 g + 25 g + 500 g = 555 g

mass percent of calcium sulfate =  12 g/555 g * 100/1 = 2.2 %

mass percent of sodium nitrate =  18 g/ 555 g  * 100/1 = 3.2 %

mass percent of potassium chloride = 25 g / 555 g  * 100/1 = 4.5%

mass percent of water =  500 g / 555 g  * 100/1 =90.1%

e) Total mass present = 125 g + 1500g = 1625 g

Mass percent of NaCl =  125 g/1625 g * 100/1 = 7.7%

f) Total volume of solution = 15 L +  28 L  = 43 L

percent by volume of acetone = 15 L/43 L * 100/1 =  34.9%

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can u help me with this

Answers

Answer:

c

Explanation:

the reason is because your a homosiejenenddj

When a 21.2 mL sample of a 0.411 M aqueous hydrofluoric acid solution is titrated with a 0.371 M aqueous barium hydroxide solution, what is the pH after 17.6 mL of barium hydroxide have been added

Answers

For a 21.2 mL sample of a 0.411 M aqueous hydrofluoric acid solution,  the pH after 17.6 mL of barium hydroxide has been added is mathematically given as

pH=3.332

What is the pH after 17.6 mL of barium hydroxide has been added?

Generally, the equation for the  mole of HF is mathematically given as

mole of HF=molarity*volume

Therefore

mole of HF=0.361*19.2

mole of HF=6.931mmol

The chemical equation

HF+kOH⇆KF+H2O

Therefore

pH=pKa+log(Kf/HF)

pH=3.15+log(6.931*53.6/53.6*4.558)

pH=3.332

In conclusion, The pH

pH=3.332

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If a watershed suddenly receives a great deal of rainfall, what will happen to its wetlands and rivers?

Answers

Answer:

Depending on the actual amount of water, it's going to overfill.

Explanation:

If your watershed is already one that has a lot of water and is always filled, it's likely that your wetlands and rivers will start to overfill, causing a form of flooding.

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I hope this helps!

-No one

Write an equation that represents the action in water of hypoiodous acid ( HOI ) as a Brønsted–Lowry acid.

Answers

Taking into account the Brønsted-Lowry acid-base theory, the reaction between hypoiodous acid and water is:

HOI + H₂O ⇄ OI⁻ + H₃O⁺

Brønsted-Lowry acid-base theory

The Brønsted-Lowry acid-base theory (or the Brønsted-Lowry theory) identifies acids and bases based on whether the species accepts or donates protons or H⁺.

According to this theory, acids are proton donors while bases are proton acceptors. That is, an acid is a species that donates an H⁺ proton while a base is a chemical species that accepts an H⁺ proton from the acid.

So, reactions between acids and bases are H⁺ proton transfer reactions, causing the acid to form its conjugate base and the base to form its conjugated acid by exchanging a proton.

Reaction between hypoiodous acid and water

In this case, the reaction between hypoiodous acid and water is:

HOI + H₂O ⇄ OI⁻ + H₃O⁺

where HOI acts as an acid because it donates a potron, while water acts as a base because it accepts the proton donated by HOI.

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2AI(NO3)3 + 3Na2CO3 → Al2(CO3)3(s) + 6NaNO3

What is the ratio of moles of AI(NO3)3 to moles Na2CO3?​

Answers

The ratio of moles of AI(NO3)3 to moles Na2CO3 in the reaction is 2:3

In the reaction 2 moles of AI(NO3)3 reacted with 3 moles Na2CO3 so the ratio of the moles is 2 is to 3 represented as 2:3


hope it helps

you find a mysterious white powder in your kitchen. it could be cream of tartar (pH=5), sugar (pH=7), baking soda (pH=8), or drain cleaner (pH=14). explain which pH indicator(s) you would use to determine the unknown substance.

Answers

The pH indicators that would be used to determine the unknown substance are :

Litmus Methyl orangePhenol Red

pH Indicators

The pH indicators that can be used to identify the mysterious white powder in the kitchen must be an acid-base indicator such as Litmus or other form of effective pH indicators like methyl orange and Phenol red.

The pH value of the substance as indicated by the acid-base indicators will help to determine what the mysterious white powder is based on the varying pH of the substances resembling the white powder.

Hence we can conclude that The pH indicators that would be used to determine the unknown substance are :Litmus , Methyl orange, Phenol Red.

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