A 250 grams sample of an unknown substance was heated from 35 degree Celsius to 50 degree Celsius. The substance absorbed 7,454 J of energy. What is the specific heat of the substance? Identify if the reaction is exothermic or endothermic

In the formation of 1 formula unit of ScBr₃, 3 electrons are transferred.

Let's consider the following balanced redox reaction.

2 Sc + 3 Br₂ ⟶ 2 ScBr₃

We can identify both half-reactions.

Oxidation: 2 Sc ⟶ 2 Sc⁺³ + 6 e⁻

Reduction: 6 e⁻ + 3 Br₂ ⟶ 6 Br⁻

As we can see, 6 electrons are involved in the formation of 2 formula units of ScBr₃. Thus, 3 electrons are involved in the formation of 1 formula unit of ScBr₃.

In the formation of 1 formula unit of ScBr₃, 3 electrons are transferred.

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The concentrations  Cu(NH3)42+ at equilibrium is  [Cu(NH3)42+] = 1.70 × 1013 * (0.0200M) * (0.300M)^4.

The concentrations  of Cu2+ is [Cu(NH3)42+] + [Cu2+]

The concentrations  of NH3 is 4[Cu(NH3)42+] + 4[NH3]

Equilibrium concentration is described as a state when the rate of forward reaction in a chemical reaction becomes equal to the rate of backward reaction.

The equilibrium constant expression for the formation of the complex ion Cu(NH3)42+ is:

Kf = [Cu(NH3)42+] / [Cu2+] * [NH3]^4

where [Cu(NH3)42+], [Cu2+], and [NH3] are the molar concentrations at equilibrium.

The initial concentrations of Cu2+ and NH3 are 0.0200 M and 0.300 M respectively.

We have that Kf = 1.70 × 1013, we then  rearrange the equation to solve for [Cu(NH3)42+]:

1.70 × 1013 = [Cu(NH3)42+] / (0.0200M) * (0.300M)^4

[Cu(NH3)42+] = 1.70 × 1013 * (0.0200M) * (0.300M)^4

Therefore at equilibrium, the concentration of Cu(NH3)42+ is [Cu(NH3)42+] = 1.70 × 1013 * (0.0200M) * (0.300M)^4

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Answer:

False

Explanation:

The given statement stating that resistance  is the slowing of the flow of electrons and where some of the electrical energy is converted into heat is true and it is a opposite of conduction.

Conduction is defined as a process as a means of which heat is transferred from the hotter end of the body to it's cooler end.Heat flows spontaneously from a body which is hot to a body which is cold.

In the process of conduction,heat flow is within the body and through itself.In solids the conduction of heat is due to the vibrations and collisions of molecules while in liquids and gases it is due to the random motion of the molecules .

When conduction takes place, heat is usually transferred from one molecule to another as they are in direct contact with each other.There are 2 types of conduction:1) steady state conduction 2) transient conduction.According to the type of energy conduction is of three types:

1) heat conduction

2) electrical conduction

3)sound conduction

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The structure of  the alkyne 4 - decyne is shown in the image attached.

Alkyne functional group compounds with a triple bond made of carbon and carbon contain 4-decyne (C). The triple bond is found at the fourth carbon position in the ten-carbon chain (decyne) of 4-decyne.

Nine hydrogen atoms (H) are joined to the first nine carbon atoms (C), starting from the left side.

In conclusion, 4-decyne is made up of a chain of ten carbon atoms, with the fourth carbon atom serving as the center of a carbon-carbon triple bond (C). Except for the carbon involved in the triple bond, all carbon atoms are connected to hydrogen atoms.

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Answer:  96 g O2

Explanation:

this is combustion

CH4 + 2 O2  --> CO2 + 2 H2O

24 g CH4  X 1 mole Ch4 / 16.043 g CH4) X ( 2 moles O2 / 1 moles CH4) X

( 31.999 G O2 / 1 mole O2 ) = 95.74 g O2 = 96 g O2 in correct sig figs

Answer:

The daughter nuclides of these two decay processes are \(^{192}_{78}Pt \) and \(^{192}_{76}Os\).

Explanation:

The beta emission is represented by:

A = (Z + 1) + (n - 1) = is invariant

n: neutron

p: proton

\(^{A}_{Z}X \rightarrow ^{A}_{Z+1}Y\)

Hence, the daughter nuclide of the beta emission of Ir-192 is:

\(^{192}_{77}Ir \rightarrow ^{192}_{78}Pt\)      

Now, electron capture is represented by:

A = (Z - 1) + (n + 1) = is invariant

\(^{A}_{Z}X \rightarrow ^{A}_{Z-1}Y\)

Then, the daughter nuclide of the electron capture of Ir-192 is:

\(^{192}_{77}Ir \rightarrow ^{192}_{76}Os\)    

Therefore, the daughter nuclides of these two decay processes are \(^{192}_{78}Pt \) and \(^{192}_{76}Os\).

I hope it helps you!

The pH of the solution made by mixing 15.0cm³ 0.1M NaOH and 35.0 cm³ 0.2 M HCOOH would be 2.39.

The first step in solving this problem is to write the balanced chemical equation for the reaction between NaOH and HCOOH:

NaOH + HCOOH → NaCOOH + H2O

Next, we need to calculate the moles of each reactant:

moles NaOH = 0.1 mol/L x 0.015 L = 0.0015 moles

moles HCOOH = 0.2 mol/L x 0.035 L = 0.007 moles

Since NaOH and HCOOH react in a 1:1 stoichiometry, we know that 0.0015 moles of NaOH reacts with 0.0015 moles of HCOOH. This leaves 0.007 - 0.0015 = 0.0055 moles of HCOOH unreacted.

Now, we need to use the equilibrium constant (Ka) for the reaction between HCOOH and water to determine the concentration of H+ ions in the solution:

HCOOH + H2O ⇌ H3O+ + HCOO-

Ka = [H3O+][HCOO-]/[HCOOH]

We are given the value of Ka, so we can use it to find the concentration of H+ ions:

Ka = 1.82 × 10^-4 M

[H3O+] = [HCOO-] = x (let's assume that the initial concentration of HCOOH is much larger than x, so we can assume that x is negligible compared to the initial concentration of HCOOH)

[HCOOH] = 0.0055 moles / 0.05 L = 0.11 M

Ka = (x^2) / (0.11 - x)

Since x is negligible compared to the initial concentration of HCOOH, we can simplify the equation to:

Ka = (x^2) / 0.11

Solving for x, we get:

x = sqrt(Ka * [HCOOH]) = sqrt(1.82 x 10^-4 * 0.11) = 0.0041 M

Therefore, [H+] = 0.0041 M

Finally, we can use the definition of pH to calculate the pH of the solution:

pH = -log[H+] = -log(0.0041) = 2.39

Therefore, the pH of the solution is 2.39.

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Answer:

Hello attached below is the data found in Aleks Data tab

answer :

i) N0

ii) N0

iii) YES ,  pH of highest solubility = 5

Explanation:

i) For CuBr

solubility does not change with pH  hence answer = NO

ii) For MgCl2

solubility does not change with pH hence the answer = NO

iii) For Ba(OH) 2

Solubility does change with pH hence the answer = YES

and the pH at which the highest solubility will occur is = 5

attached below is the reason for the answers given

In 15.0 mL of a 2.5 molar magnesium chloride solution, there are approximately 4.51 × 10^{22} chloride ions.

An inorganic compound composed of one magnesium ion and two chloride ions.

We must first determine the number of moles of MgCl_2 in the solution,

moles of solute = concentration × volume (in liters)

Converting the solution's volume from milliliters to liters,

15.0 mL = 15.0 × 10^{-3} L

moles of MgCl_2 = 2.5 mol/L × 15.0 × 10^{-3} L = 0.0375 moles

The solution contains the following number of chloride ions:

number of Cl^{-} ions = 2 × moles of MgCl_2

Substitute the value of moles of MgCl_2,

number of Cl^{-} ions = 2 × 0.0375 moles = 0.075 moles

by using Avogadro's number:

number of Cl^{-} ions = 0.075 moles × 6.02 × 10^{23} ions/mol ≈ 4.51 × 10^{22} ions

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The correct option is 2.

A 88

B 94

C 100

To solve this problem, we need to use our knowledge of how streams flow and how velocity changes in different parts of the stream.

Typically, streams flow fastest in the center of the channel and slowest along the edges, due to friction with the banks and bottom of the stream.

Given that it lies in the middle of the stream's two extreme velocities, option 2, which equals 94, is probably the right response. The velocity near the channel's middle is probably closer to 100 because the stream runs there the quickest.

On the other hand, it is likely that the velocity near the edges is closer to 88 since the stream runs more slowly along the edges due to friction with the banks and streambed. Consequently, a velocity of 94 is the most logical choice because it is within the range that is  predicted by the velocity distribution of a stream.

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Answer:

It prevent the solution from making 100% pure alum.

Explanation:

Large chunks could be bad if we make 100% pure alum because the large chunks prevent the production of 100% pure alum so for making 100% pure alum, large chunks will be removed from the solution or process. Alum is a chemical compound having salt of sulfate attached with aluminum in hydrated form i. e. presence of water. It is widely used in vaccines and for the purification of drinking water.

Answer:

The periodic table is a tabular array of the chemical elements organized by atomic number, from the element with the lowest atomic number, hydrogen, to the element with the highest atomic number, oganesson.

Answer:

A periodic table is a table filled with chemical elements. They are organised by their atomic number and how many electrons each element contains

This representation suggests that the element is phosphorus (P) with a mass number of 30, which is incorrect. The correct mass number for phosphorus is approximately 30.97. The incorrect representation for a neutral atom is 36Li

To determine the correct representation for a neutral atom, we need to consider the atomic number (Z) and mass number (A) of the element. The atomic number represents the number of protons in the nucleus, while the mass number represents the sum of protons and neutrons.

Let's analyze the given representations:

36Li:

This representation suggests that the element is lithium (Li) with a mass number of 36, which is incorrect. The correct mass number for lithium is approximately 6.94.

613C:

This representation suggests that the element is carbon (C) with a mass number of 13, which is correct. Carbon has different isotopes, and 13C represents one of its stable isotopes.

3063Cu:

This representation suggests that the element is copper (Cu) with a mass number of 63, which is correct. Copper has different isotopes, and 63Cu represents one of its stable isotopes.

1530P:

This representation suggests that the element is phosphorus (P) with a mass number of 30, which is incorrect. The correct mass number for phosphorus is approximately 30.97.

Therefore, the incorrect representation for a neutral atom is 36Li, as it does not match the known properties of lithium.

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Answer:

C6H12O6

Explanation:

C6H12O6

Answer:

A

Explanation:

To calculate questions like this, you need to make use of the equation below:

E = hν

E is the energy, h is Planck's constant, and ν is the frequency.

Also, another important formula you need for this question is the following:

ν = c / λ

ν is the frequency, c is the speed of light, and λ is the wavelength.

Therefore, E = hν = hc/λ.

Also remember to convert nm wavelength to meters.

To answer the question, E = hc/λ = ((6.626*10^-34 J•s)(3*10^8 m/s))/(4.45*10-7 m) = 4.42 • 10^-19 J = A

After the reaction is finished, N2 has a partial pressure of 0.995 atm.

Provide three strategies for accelerating a chemical reaction. providing heat, increasing the reactants' surface area or concentration, or adding a catalyst are all ways to raise the temperature.

A catalyst is a chemical that can be included in a reaction to speed up the process without being consumed. Catalysts typically reduce a process's activation energy or change its mechanism. Proteins called enzymes serve as catalysts in biological reactions.

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Explanation:

We can use the Arrhenius equation to solve this problem:

k = Ae^(-Ea/RT)

where k is the rate constant, A is the pre-exponential factor, Ea is the activation energy, R is the gas constant (8.314 J/mol*K), and T is the temperature in Kelvin.

Assuming that the pre-exponential factor and the frequency factor are constant, we can compare the rate constants at two different temperatures to find the percentage of molecules at or above the activation energy:

k1/k2 = exp[(Ea/R)(1/T2 - 1/T1)]

At 500 K, we have:

k1 = Ae^(-Ea/RT1)

At a higher temperature, say 600 K, we have:

k2 = Ae^(-Ea/RT2)

Dividing k1 by k2:

k1/k2 = e^[(Ea/R)(1/T2 - 1/T1)]

k1/k2 = e^[(15.10 kJ/mol)/(8.314 J/mol*K)((1/600 K) - (1/500 K))]

k1/k2 = 2.34

So at 500 K, the rate constant is 1/2.34 times the rate constant at 600 K. This means that only about 42.7% of the molecules are at or above the activation energy at 500 K.

The sample that uses the substance that Jacob and Natalie should use to make a cold pack that will do the best job of keeping food cool is sample 2, because it absorbs the most energy (option B).

Endothermic refers to a chemical reaction that absorbs heat energy from its surroundings. This ensures that the temperature of the surroundings is cool or has a lower temperature.

According to this question, Jacob and Natalie are asked by their science teacher to design a warming or cooling device. They make use of certain substances, however, sample 2 has the lowest final temperature of -4°C.

This shows that sample 2 absorbs the most energy, hence, would be the best for keeping the food cool.

The incomplete question is as follows:

Jacob and Natalie are asked by their science teacher to design a warming or cooling device. They decide to design a cold pack that can be used to help keep food cool. Jacob and Natalie read about different substances that can be used inside cold packs and learn that most cold packs use endothermic reactions to cool objects.

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Answer:

Uranium experiences a stronger net force holding its protons and neutrons together than barium.

Explanation:

Answer:

cannot be measure

Hope this helps :) !!!

Krypton, Chromium, and Oxygen with the following symbols Kr-13, Cr-2, and O-15 respectively have 23 electrons.

The atomic number of an atom determines the number of electrons it has. When the number of protons is equivalent to the number of electrons, the atom is electrically neutral. An anion, on the other hand, is an atom with a negative charge. It has gained an electron or two, or even more. Below are the chemical symbols for three different atoms or atomic anions with 23 electrons.Krypton:Kr has an atomic number of 36, indicating that it has 36 electrons. However, if we add 13 electrons to it, the total number of electrons becomes 49. Krypton with 13 additional electrons becomes Kr-13, with a total of 49 electrons.Chromium:Cr has an atomic number of 24, indicating that it has 24 electrons. Adding two more electrons to it, the total number of electrons becomes 26. The atomic anion with 26 electrons is Cr-2.Oxygen:Oxygen has an atomic number of 8, indicating that it has 8 electrons. However, if we add 15 electrons to it, the total number of electrons becomes 23. Oxygen with 15 additional electrons becomes O-15, with a total of 23 electrons.

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44.4 g is the mass of Aluminum Oxide is required for the given chemical reaction 3 BaSO\(_4\) + Al\(_2\)O\(_3\)—> 3 BaO + Al\(_2\)(SO\(_4\))\(_3\).

It is the most fundamental characteristic of matter as well as one of the essential quantities in physics. Mass is a term used to describe how much matter is there in a body. The kilogramme (kg) is the international standard of mass. A body's bulk remains constant at all times. only in rare instances where an enormous quantity of energy is supplied to or taken away from a body.

3 BaSO\(_4\) + Al\(_2\)O\(_3\)—> 3 BaO + Al\(_2\)(SO\(_4\))\(_3\)

moles of BaO =202/ 153.3

                        =1.32

moles of Al\(_2\)O\(_3\) = 1/3×1.32=0.44

mass of Al\(_2\)O\(_3\) = 0.44×101.9=44.4 g

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4.7 × 10²⁴ atoms Li

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Stoichiometry

Step 1: Define

7.8 mol Li

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

Step 4: Check

We are told to round to 2 sig figs. Follow sig fig rules and round.

4.69716 × 10²⁴ atoms Li ≈ 4.7 × 10²⁴ atoms Li

Answer:

B<Ga<Al

Explanation:

Hope this helps

Answer:

Explanation:

Given data:

A) Volume of CO₂ = 0.100 L

Pressure = 307 torr

Temperature = 26°C

Mass of CO₂ = ?

Solution:

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K  

T = temperature in kelvin

Now we will convert the temperature.

26+273 = 299 K

307 torr/760 = 0.40 atm

0.40 atm × 0.100 L = n × 0.0821 atm.L/ mol.K  ×  299 K

0.04 atm.L =  n × 24.55 atm.L/ mol

n = 0.04 atm.L  / 24.55 atm.L/ mol

n = 0.002 mol

Mass of CO₂:

Mass = number of moles × molar mass

Mass = 0.002 mol × 44 g/mol

Mass = 0.088 g

Given data:

b) Volume of C₂H₄ = 8.75 L

Pressure = 378.3 Kpa

Temperature = 483 K

Mass of C₂H₄  = ?

Solution:

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K  

T = temperature in kelvin

378.3KPa/101 = 3.73 atm

by putting values

3.73 atm × 8.75 L = n × 0.0821 atm.L/ mol.K  ×  483 K

32.64 atm.L =  n × 39.65 atm.L/ mol

n = 32.64 atm.L / 24.55 atm.L/ mol

n = 0.82 mol

Mass of C₂H₄ :

Mass = number of moles × molar mass

Mass =  0.82 mol × 28 g/mol

Mass = 22.96 g

c)

Given data:

A) Volume of Ar = 221 mL

Pressure = 0.23 torr

Temperature = -54°C

Mass of Ar = ?

Solution:

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K  

T = temperature in kelvin

Now we will convert the temperature.

-54+273 = 219 K

0.23 torr/760 = 0.0003 atm

221 mL/1000 = 0.221 L

0.0003 atm × 0.221 L = n × 0.0821 atm.L/ mol.K  ×  219 K

6.63×10⁻⁵ atm.L =  n × 17.98 atm.L/ mol

n = 6.63×10⁻⁵ atm.L  / 17.98 atm.L/ mol

n = 0.37×10⁻⁵  mol

Mass of Ar:

Mass = number of moles × molar mass

Mass = 0.37×10⁻⁵ mol × 39.9 g/mol

Mass = 14.76 ×10⁻⁵g

The number of moles the gas can be used to calculate the mass of the gas in each case.

Using;

a) PV = nRT

P = 307 torr or 0.4 atm

T =  26 °C + 273 = 299 K

V = 0.100 L

R = 0.082 atm LK-1mol-1

n = PV/RT

n =  0.4 atm ×  0.100 L / 0.082 atm LK-1mol-1 × 299 K

n = 0.00163 moles

Mass of CO2 =  0.00163 moles × 44 g/mol = 0.072 g

b) Again;

P = 378.3 kPa or 3.75atm

T = 483 K

V =  8.75 L

R = 0.082 atm LK-1mol-1

n = PV/RT

n = 3.75atm ×  8.75 L/0.082 atm LK-1mol-1 × 483 K

n = 0.83 moles

Mass of C2H4 =  0.83 moles × 28 g/mol = 23.24 g

c) Again;

P =  0.23 torr  or 0.0003 atm

V =  221 mL or 0.221 L

T =  -54 °C​ + 273 = 219 K

R = 0.082 atm LK-1mol-1

n = PV/RT

n =  0.0003 atm ×  0.221 L/0.082 atm LK-1mol-1 ×  219 K

n = 3.69 × 10^-6 moles

Mass of Ar  =  3.69 × 10^-6 moles × 40 g/mol

Mass of Ar  = 1.48 × 10^-4 g

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1a. The volume (in cm³) of the block is 1042.734 cm³

1b. The volume (in L) of the block is 1.04 L

1c. The density (in g/mL) of the block is 0.907 g/mL

1d. The block will not sink

The volume of the block in cm³ can be obtained as follow:

Volume of block = dimension

Volume of block = 11.1 cm × 154 mm × 0.061 m

Volume of block = 11.1 cm × (154 / 10) cm × (0.061 × 100) m

Volume of block = 11.1 cm × 15.4 cm × 6.1 cm

Volume of block (in cm³) = 1042.734 cm³

The volume of the block in L can be obtained as follow:

1000 cm³ = 1 L

Therefore,

1042.734 cm³ = (1042.734 cm³ × 1 L) / 1000 cm³

1042.734 cm³ = 1.04 L

Thus, we can say that the volume of block (in L) is 1.04 L

We can obtain the density in g/mL as shown below:

Density = mass / volume

Density of block = 9.46×10² / 1042.734

Density of block = 0.907 g/mL

First, we shall determine the density of the liquid. Details below:

Density = mass / volume

Density of liquid = 724.11 / 780

Density of liquid = 0.928 g/mL

Now, we shall compare the density of the block and liquid to detect whether or not the block will sink. Details below:

Since the density of the block is smaller than that of the liquid, the block will not sink in the liquid.

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Answer:

Computers are more useful for quick calculations.

Computers are easier to transport to remote locations.

Computers have lower power consumption.

Computers hold larger amounts of data.

give brainliest pls

Answer: you have to talk to someone who wont mind wanting to wanting to like you a lot like that.

Explanation:  I wish I could be able to talk to someone who would want to get to like me like that, so its a very relatable situation.