Which of the following ions would represent the ion of an element from Group 2 on the Periodic Table? A2+ Y3+ X2- Z+

Positrons are spontaneously emitted from the nuclei of

Leto [7]

Positrons are spontaneously emitted from the nuclei of potassium -37.

4 0

3 years ago

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Mole Conversion: How many molecules are there in 6.70 moles of methane, CH4

raketka [301]

Answer:

Explanation:

1 mol of methane = 6.02 * 10^23 molecules

6.70 mol of methane = x

Cross multiply

x = 6.70 * 6.02 * 10^23

x = 4.033 * 10^23 molecules.

8 0

3 years ago

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A helium-filled balloon at 310.0 K and 1 atm, contains 0.05 g He, and has a volume of 1.21 L. It is placed in a freezer (T = 235

trapecia [35]

Answer : The value of $\Delta E$ of the gas is 2.79 Joules.

Explanation :

First we have to calculate the moles of helium.

$\text{Moles of helium}=\frac{\text{Mass of helium}}{\text{Molar mass of helium}}$

Molar mass of helium = 4 g/mole

$\text{Moles of helium}=\frac{0.05g}{4g/mole}=0.0125mole$

Now we have to calculate the heat.

Formula used :

$q=nc_p\Delta T\\\\q=nc_p(T_2-T_1)$

where,

q = heat

n = number of moles of helium gas = 0.0125 mole

$c_p$ = specific heat of helium = 20.8 J/mol.K

$T_1$ = initial temperature = 310.0 K

$T_2$ = final temperature = 235.0 K

Now put all the given values in the above formula, we get:

$q=nc_p(T_2-T_1)$

$q=(0.0125mole)\times (20.8J/mol.K)\times (235.0-310.0)K$

$q=-19.5J$

Now we have top calculate the work done.

Formula used :

$w=-p\Delta V\\\\w=-p(V_2-V_1)$

where,

w = work done

p = pressure of the gas = 1 atm

$V_1$ = initial volume = 1.21 L

$V_2$ = final volume = 0.99 L

Now put all the given values in the above formula, we get:

$w=-p(V_2-V_1)$

$w=-(1atm)\times (0.99-1.21)L$

$w=0.22L.artm=0.22\times 101.3J=22.29J$

conversion used : (1 L.atm = 101.3 J)

Now we have to calculate the value of $\Delta E$ of the gas.

$\Delta E=q+w$

$\Delta E=(-19.5J)+22.29J$

$\Delta E=2.79J$

Therefore, the value of $\Delta E$ of the gas is 2.79 Joules.

3 0

3 years ago

An atom of lithium (Li) forms an ionic bond with an atom of chlorine (Cl) to form lithium chloride. How are the valence electron

miskamm [114]

Answer: Option (D) is the correct answer.

Explanation:

Atomic number of lithium is 3 and electrons in its shell are distributed as 2, 1. Atomic number of chlorine is 17 and electrons in its shell are distributed as 2, 8, 7.

Thus, we can see that lithium has 1 extra electron and chlorine has deficiency of 1 electron. Therefore, in order to gain stability lithium will transfer its 1 extra electron to chlorine atom.

Thus, we can conclude that electrons are transferred from the lithium atom to the chlorine atom.

6 0

3 years ago

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How many grams of ammonia gas can be formed from 54.1 g of hydrogen gas

Murrr4er [49]

Answer:

304.19 g

Explanation:

M(H2) = 2*1 = 2 g/mol

54.1 g H2 * 1 mol H2/2gH2 = 27.05 mol H2

3H2 + N2 ------> 2NH3

from reaction 3 mol 2 mol

given 27.05 mol x mol

x = 27.05*2/3 = 18.03 mol NH3

M(NH3) = 14 +3*1 = 17 g/mol

18.03 mol NH3 * 17 g NH3/ 1 mol NH3 ≈ 307 g

Closeet answer is 304.19 g.

4 0

3 years ago