If 20.0 g of Pb transfers 4950 J of energy into 50.0 g of water, how much would the temperature of the water change?​ By how much would the metal cool?

Answer:  The transition elements are in the d-block, and in the d-orbital have valence electrons. They can form several states of oxidation and contain different ions. Inner transition elements are in the f-block, and in the f-orbital have valence electrons.

Explanation:

Transition metals are elements that have partially filled the d-orbital while in f-block elements the electron is filled in the f-orbital.

Transition elements or transition metals are elements that have partially filled d-orbitals.  An element that has the ability to produce cations with an incompletely filled d-orbital or an element having a d-subshell that is incompletely filled with electrons.

Any element which belongs to the d-block of the modern periodic table or is present in group 3 to 12 is considered to be a transition metal.

The f-block elements are those in which the f-orbital gets filled up by electrons. The f-block elements have electrons 1 to 14 in their f-orbital, and 0 to 1 in their d-orbital.

The f-block element is classified into two series one lanthanides and other actinides corresponding to the filling of electrons in 4f and 5f orbitals respectively. The f- block elements are placed at the bottom of the modern periodic table.

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Here option 2 is correct ^H = +48 kJ, AS = +135 J/K at 400 K for a reaction to be spontaneous.

What is a spontaneous reaction ?

A spontaneous reaction is one that favors the creation of products under the reaction's current conditions. A bonfire that is raging and exothermic is an illustration of a spontaneous reaction (there is a decrease in the energy of the system as energy is released to the surroundings as heat)

If both ΔH0 and ΔS0 are positive then reaction will be spontaneous at high temperature

Here option 2 is correct ^H = +48 kJ, AS = +135 J/K at 400 K for a reaction to be spontaneous.

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Answer;

Explanation:

Here, we want to select the option that is not true from the given set of options

We take a look at each of the statements as follows:

a) This is true.

The alpha helix is a spiral arrangement in which the amino acid chains are arranged. It is also associated with secondary structure

b) This is false

Since a protein can be a single unit. This means that not all are associated with a quarternary level

c) This is ture

d) This is true

Answer:

2 & 3

Explanation:

Becasue they have only 1 product

Explanation: heat is transferred from the hot water to the cold water until they reach the same temperature

Answer:Molecular Formula SO2

Hybridization Type sp2

Bond Angle 119o

Geometry V-Shaped or Bent

Explanation:

hope this helped <3

ANSWER

The number of moles of CO2 is 2.69 moles

EXPLANATION

Given that;

The mass of CO2 is 118.6 grams

Follow the steps below

The molar mass of CO2 is 44.01 g/mol

Therefore, the number of moles of CO2 is 2.69 moles

Answer:

1.) 17.76 moles H₂O

2.) 323.1 g HCN

Explanation:

1.) An equation is balanced when there is an equal amount of each element on both sides of the reaction. The quantities can be modified by adding coefficients in front of the molecules.

The unbalanced equation:

Al₄C₃(s) + H₂O -----> Al(OH)₃(s) + CH₄(g)

Reactants: 4 aluminum, 3 carbon, 2 hydrogen, 1 oxygen

Products: 1 aluminum, 1 carbon, 7 hydrogen, 3 oxygen

The balanced equation:

Al₄C₃(s) + 12 H₂O -----> 4 Al(OH)₃(s) + 3 CH₄(g)

Reactants: 4 aluminum, 3 carbon, 24 hydrogen, 12 oxygen

Products: 4 aluminum, 3 carbon, 24 hydrogen, 12 oxygen

Now that the equation is balanced, you can use the relevant coefficients to construct a mole-to-mole ratio. This will allow you to convert between moles Al₄C₃ to moles H₂O.

 1.48 moles Al₄C₃           12 moles H₂O
----------------------------  x  ------------------------  =  17.76 moles H₂O
                                         1 mole Al₄C₃

2.) To find the mass of HCN, you need to (1) convert grams NH₃ to moles NH₃ (via molar mass), then (2) convert moles NH₃ to moles HCN (via mole-to-mole from equation coefficients), and then (3) convert moles HCN to grams HCN (via molar mass). It is important to arrange the coefficients in a way that allows for the cancellation of units.

Molar Mass (NH₃): 14.009 g/mol + 3(1.008 g/mol)

Molar Mass (NH₃): 17.033 g/mol

Molar Mass (HCN): 1.008 g/mol + 12.011 g/mol + 14.009 g/mol

Molar Mass (HCN): 27.028 g/mol

2 CH₄(g) + 3 O₂(g) + 2 NH₃(g)  ------> 2 HCN(g) + 6 H₂O(g)

203.6 g NH₃            1 mole            2 moles HCN           27.028 g
---------------------  x  ----------------  x  ------------------------  x  -----------------  =
                                17.033 g           2 moles NH₃             1 mole

=  323.1 g HCN

The molar mass of compound of magnesium chloride is 95.211 g/mole while that of ammonium sulfate is 132.14 g/mole.

Molar mass of a compound or a molecule is defined as the mass of the elements which are present in it.The molar mass is considered to be a bulk quantity not a molecular quantity. It is often an average of the of the masses at many instances.

The molecular mass and formula mass are used as synonym for the molar mass.It does not depend on the amount of substance which is present in the sample.It has units of gram/mole.

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Answer:

Single-replacement reaction

Explanation:

Single-replacement reactions, aka. single-displacement reactions, involve one element/ion in a compound being replaced by another element/ion. In this case, aluminum is replacing the iron in the compound.

If you need help visualizing, the equation looks like this:

Fe₂O₃ + Al³⁺ --> Al₂O₃ + Fe³⁺

The final mass concentration of salt in the solution in g/l is 36.06 g/L.

The mass concentration of the mixture of the two salt solutions is calculated as follows:

Concentration of solution 1 = 15 g/l

mass of salt in the 250 mL solution = 15 g/l * 250 mL * 1 L/1000 mL

mass of salt in the 250 mL solution = 3.75 g

Concentration of solution = 6% (m/v)

This means that in 100 mL solution, 6 g of salt in present.

In 1000 mL or 1 L solution, 60 g of salt will be present.

Hence, the concentration of solution = 60 g/L

mass of salt in the 220 mL solution = 60 g/l * 220 mL * 1 L/1000 mL

mass of salt in the 220 mL solution = 13.2 g

Total mass of salt in the mixture = 16.95 g

Total volume of solution = 470 mL

Final mass concentration of solution = 16.95 g / 470 mL * 1000 mL/L

Final mass concentration of solution = 36.06 g/L

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The definition of a genuine solution is a homogenous mixture of two or more substances where the particle size of the material dissolved (solute) in the solvent is less than 10-9 m or 1 nm. A solution of simple sugar and water is an example of a true solution.

In the process of dissolving a solute in a solvent, a homogenous mixture known as a solution is created.

a combination of two or more materials that is homogenous. example: a water, sugar, and flavor combination (Coke). Not chemically or chemically connected, the substances are only physically combined.

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The volume in liters of 5.75 moles of CO₂ at standard temperature and pressure (STP) is 128.88L.

The volume of a given gas at STP can be calculated using the following formula;

PV = nRT

Where;

According to this question, 5.75 moles of CO₂ at standard temperature and pressure (STP). The volume of this gas can be calculated as follows;

At STP, the following applies;

1 × V = 5.75 × 0.0821 × 273

V = 128.88L

Therefore, 128.88L is the volume of the gas.

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The number of moles of the gas at 77°C and 1.33 atm occupies a volume of 50.3 L is 2.35 moles. It can found with the help of Ideal gas equation.

The ideal gas equation is formulated as : PV = nRT.

In this equation, P refers to the pressure of the ideal gas, V is the volume of the ideal gas, n is the total amount of ideal gas that is measured in terms of moles, R is the universal gas constant, and T is the temperature.

Given ;

We know ;

Formula used ;

n = PV / RT

n = 1.33 x 50.3 / 0.081 x 350k

  =  2.35 moles.

Hence, The number of moles of the gas at 77°C and 1.33 atm occupies a volume of 50.3 L is 2.35 moles

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There are 2 grams remain

Given

t1/2 = 30 years

t = 170 years

No = 100 g

Required

Remaining sample

Solution

General formulas used in decay:  

\(\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}\)

Input the value :

\(\tt Nt=100.\dfrac{1}{2}^{170/30}\\\\Nt=1.969\approx 2~grams\)

When the switch is closed, electrons flow from the solid magnesium electrode, Mg(s) to solid silver electrode, Ag(s).

Electronegativity of metals refers to the ability of the atoms of metallic elements to attract electrons from the other metallic elements.

Electronegativity increases down the activity series.

Silver (Ag) will have more tendency to attract electron more than magnesium (Mg).

Thus, when the switch is closed, electrons flow from the solid magnesium electrode, Mg(s) to solid silver electrode, Ag(s).

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Answer:

The molecular formula of X = C4 h8 O

Answer:

Show diagram so we can see

Explanation:

Answer:

An element is to a compound as an organ is to tissue

Explanation:

Answer:

cause it has more

space between molecules.

O C. Ice has a higher density than li

Explanation:

The Jobs method works because the ratio of the cations to the anions in a salt is fixed and can be determined by measuring the mass of the precipitate formed when the salt is reacted with a known quantity of a reagent.

What is Job?

In the context of chemistry, the "Jobs method" refers to a chemical technique used to determine the empirical formula of a salt. It is named after its inventor, Zdenko Hans Skraup Job (1865-1933), who was an Austrian chemist and professor of chemistry at the University of Prague.

Job is best known for his work on the synthesis and properties of organic compounds, particularly his research on indole derivatives and alkaloids. He also made important contributions to the field of physical chemistry, including the development of the Jobs method for determining the empirical formula of a salt.

The Jobs method is a chemical technique used to determine the empirical formula of a salt. It involves finding the ratio of the cations and anions in the salt by taking advantage of the precipitation reaction that occurs between the salt and a known amount of a reagent that forms an insoluble product with one of the ions in the salt.

The general steps of the Jobs method are as follows:

A known quantity of the salt is dissolved in water to form a solution.

A known quantity of a reagent is added to the solution, which reacts with one of the ions in the salt to form an insoluble precipitate.

The precipitate is filtered and dried, and the mass is measured.

The mass of the precipitate is used to calculate the moles of the ion that reacted with the reagent.

The ratio of the moles of the cation to the moles of the anion is calculated.

The ratio is then simplified to the smallest whole number ratio to determine the empirical formula of the salt.

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Answer:

3.11 is the pH of the buffer

Explanation:

The pH of a buffer is obtained using H-H equation:

pH = pKa + log [Conjugate base] / [Weak acid]

Where pH is the pH of the buffer, pKa = -log Ka = 3.14 for the citric buffer and [] could be taken as the moles of each species.

The citric acid,HX (Weak acid), reacts with NaOH to produce sodium citrate, NaX (weak base) and water:

HX + NaOH → H2O + NaX

That means the moles of NaOH added = Moles of sodium citrate produced

And the resulitng moles of HX = Initial moles - Moles NaOH added

Moles HX and NaX:

Moles NaOH = 0.100L * (0.65mol / L) = 0.065 moles NaOH = Moles NaX

Moles HX = 0.300L * (0.45mol / L) = 0.135 moles HX - 0.065 moles NaOH = 0.070 moles HX

Replacing in H-H equation:

pH = 3.14 + log [0.065mol] / [0.070mol]

pH = 3.11 is the pH of the buffer

Answer:

3.58J/g°C is the specific heat of the metal

Explanation:

The specific heat of a material is defined as the energy that 1g of the material absorbs and produce the increasing in temperature in 1°C. The equation is:

Q = S*ΔT*m

Where Q is energy = 1362J

S is specific heat of the material

ΔT is change in temperature = 42°C - 17°C = 25°C

And m is the mass of the material = 15.2g

Replacing:

S = Q / ΔT*m

S = 1362J / 25°C*15.2g

Answer:

D.) powerful microscopes ....... telescopes are for space our eyes can't see atoms and hand lenses are not gonna do you any good

Answer:

66 grams of ice would have to melt to lower the temperature of 352 mL of water from 15 °C to 0 °C.

Explanation:

To calculate the amount of ice that would have to melt to lower the temperature of 352 mL of water from 15 °C to 0 °C, we need to use the formula:

Q = m_water * c_water * ΔT_water + m_ice * Lf

where,
Q = the amount of heat transferred,
m_water = the mass of water, c_water is the specific heat capacity of water,
ΔT_water = the change in temperature of water, m_ice = the mass of ice,
Lf = the specific latent heat of fusion of ice.

First, let's calculate the amount of heat transferred to the water:

Q = m_water * c_water * ΔT_water
Q = 352 g * 1.0 cal/(g*°C) * (15-0) °C
Q = 5,280 cal

Next, we can use the specific latent heat of fusion of ice, which is 80 cal/g, to calculate the amount of heat required to melt the ice:

Q = m_ice * Lf
Q = m_ice * 80 cal/g
m_ice = Q / Lf
m_ice = 5,280 cal / 80 cal/g
m_ice = 66 g

Explanation:

An uncontrolled chain reaction is a chain of nuclear reactions that take place subsequently, but not under controlled conditions. When the number of atoms grows exponentially the reaction is not under control.

The definition of nuclear fusion is: "a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy". So in a fusion reaction small nuclei join to form a bigger nuclei.

The definition of nuclear fission is: "a reaction in which the nucleus of an atom splits into two or more smaller nuclei". So in a fission reaction a large nucleus breaks into smaller nuclei.

A fission chain reaction happens when a neutron and a fissile isotope interact with each other. This causes the release of some neutrons from the fissile nucleus. These released neutrons can interact with other fissile isotopes and cause the initiation of subsequent fission reactions. This is a controlled fission reaction. So, when extra neutrons are absorbed we have a controlled fission reaction.

The definition of critical mass is: "is the smallest amount of fissile material needed for a sustained nuclear chain reaction". So the critical mass is the amount of material necessary for a reaction to occur.

Answer:

The number of atoms grows exponentially the reaction ----> uncontrolled reaction

Small nuclei join to form a bigger nuclei ----> fusion

A large nucleus breaks into smaller nuclei ----> fission

Extra neutrons are absorbed ----> controlled reaction

This is the amount of material necessary for a reaction to occur ---> critical mass

Answer:

.............

1

a=1

because....... Na have 11 electrons

So..... the Electrons in K shell... 2

L shell 8

and m shell 1.........