Which atoms are indicated by the following configuration?

A lead mass is heated and placed in a foam cup calorimeter containing 40.0 mL of water at 17.0°C. The water reaches a temperatur

lbvjy [14]

Answer: 502 Joules

Explanation:

To calculate the mass of water, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of water = 1 g/mL

Volume of water = 40.0 mL

Putting values in above equation, we get:

$1g/mL=\frac{\text{Mass of water}}{40.0mL}\\\\\text{Mass of water}=(1g/mL\times 40.0mL)=40.0g$

When metal is dipped in water, the amount of heat released by lead will be equal to the amount of heat absorbed by water.

$Heat_{\text{absorbed}}=Heat_{\text{released}}$

The equation used to calculate heat released or absorbed follows:

$q=m\times c\times \Delta T$

q = heat absorbed by water

$m$ = mass of water = 40.0 g

$T_{final}$ = final temperature of water = 20.0°C

$T_{initial$ = initial temperature of water = 17.0°C

$c$ = specific heat of water= 4.186 J/g°C

Putting values in equation 1, we get:

$q=40.0\times 4.186\times (20.0-17.0)]$

$q=502J$

Hence, the joules of heat were re-leased by the lead is 502

5 0

3 years ago

Which layer of Earth has partially melted material that moves the tectonic plates? Crust, Inner core, Mantle, Outer core

Elena L [17]

This question is very unspecific, but it is probably the Mantle. If that is wrong try Crust.<span />

4 0

3 years ago

Read 2 more answers

Given K = 3.61 at 45°C for the reaction A(g) + B(g) equilibrium reaction arrow C(g) and K = 7.19 at 45°C for the reaction 2 A(g)

Firlakuza [10]

Answer:

K = 0.55

Kp = 0.55

mol fraction B = 0.27

Explanation:

We need to calculate the equilibrium constant for the reaction:

C(g) + D(g) ⇄ 2B(g) K₁= ? (1)

and we are given the following equilibria with their respective Ks

A(g) + B(g) ⇄ C(g) K₂= 3.61 (2)

2 A(g) + D(g) ⇄ C(g) K₃= 7.19 (3)

all at 45 ºC.

What we need to do to solve this question is to manipulate equations (2) and (3) algebraically to get our desired equilibrium (1).

We are allowed to reverse reactions, in that case we take the reciprocal of K as our new K' ; we can also add two equilibria together, and the new equilibrium constant will be the product of their respective Ks .

Finally if we multiply by a number then we raise the old constant to that factor to get the new equilibrium constant.

With all this in mind, lets try to solve our question.

Notice A is not in our goal equilibrium (3) and we want D as a reactant . That suggests we should reverse the first equilibria and multiply it by two since we have 2 moles of B as product in our equilibrium (1) . Finally we would add (2) and (3) to get (1) which is our final goal.

2C(g) ⇄ 2A(g) + 2B(g) K₂´= ( 1/ 3.61 )²

₊

2 A(g) + D(g) ⇄ C(g) K₃ = 7.19

C(g) + D(g) ⇄ 2B(g) K₁ = ( 1/ 3.61 )² x 7.19

K₁ = 0.55

Kp is the same as K = 0.55 since the equilibrium constant expression only involves gases.

To compute the last part lets setup the following mnemonic ICE table to determine the quantities at equilibrium:

pressure (atm) C D B

initial 1.64 1.64 0

change -x -x +2x

equilibrium 1.64-x 1.64- 2x

Thus since

Kp =0.55 = pB²/ (pC x pD) = (2x)²/ (1.64 -x)² where p= partial pressure

Taking square root to both sides of the equation we have

√0.55 = 2x/(1.64 - x)

solving for x we obtain a value of 0.44 atm.

Thus at equilibrium we have:

(1.64 - 0.44) atm = 1.20 atm = pC = p D

2(0.44) = 0.88 = pB

mole fraction of B = partial pressure of B divided into the total gas pressure:

X(B) = 0.88 / ( 1.20 + 1.20 + 0.88 ) = 0.27

8 0

3 years ago

In an ion with an unknown charge, the total mass of all the electrons was determined to be 2.19 ✕ 10−26 g, while the total mass

Ilya [14]

Answer:

$\large \boxed{\text{Fe$^{{2+}}$}}$

Explanation:

1. Number of electrons

$\text{Number of electrons} = 2.19 \times 10^{-26}\text{ g} \times \dfrac{\text{1 electron}}{9.109 \times 10^{-28}\text{ g}} = \text{24 electrons}$

2. Number of protons

$\text{Number of protons} = 4.34 \times 10^{-23}\text{ g} \times \dfrac{\text{1 proton}}{1.673 \times 10^{-24}\text{ g}} = \text{26 protons}$

3. Identify the ion

An atom with 26 protons is iron, Fe.

A neutral atom of iron would have 26 electrons.

The ion has only 24 electrons, so it has lost two. The ion must have a charge of +2.

$\text{The symbol for the ion is $\large \boxed{\textbf{Fe$^{\mathbf{2+}}$}}$}$

4 0

2 years ago

Nitrogen ion (Nitride) is ... Cation/Anion/Neither? # of protons? # of electrons? Charge (1-, 2-, 3-, 1+, 2+, 3+, or 0) Number o

OLga [1]

Answer:

3- is the charge and 8 dots on its Lewis dot structure.

Explanation:

Hello there!

In this case, since nitrogen is an element with five valence electrons (electrons on its outer shell), we infer that it needs three bonds to complete the octet, for which its charge, when forming nitride ions is 3-, which means it has received three electrons. Thus, when drawing the Lewis dot structure, it is evident that is will have 5+3 = 8 dots due to the electron reception.

Regards!

8 0

2 years ago