Answer:
145 grams of a 0.480 % KCN solution contains 697 mg of KCN.
Explanation:
w/w % : The percentage mass or fraction is mass of the of solute present in 100 grams of the solution.
given = w/w% = 0.480 %
Mass of solute that KCN = 697 mg = 0.697 g
(1 mg = 0.001 g)
Mass of the solution = ? = x
x = 145.21 g ≈ 145 g
145 grams of a 0.480 % KCN solution contains 697 mg of KCN.
40 electrons
Explanation:
The N for silicon tetrachloride, SiCl₄ is 40 electrons. The needed electrons that would be used to complete the lewis structure of the compound is actually 40 electrons. This number of electron will help the compound attain a noble configuration.
- The compound SiCl₄ is a covalent one. Here, there is sharing of electrons between two atoms.
- In drawing the electron dot formula, one must take into account the Available electrons and the Needed electrons.
- The Available electrons are sum of the valence electrons that can be accessed for the bonding. Si has 4 valence electrons, Cl has 7 valence electrons this makes a total of 4 + 7(4 atoms of chlorine), 32 available electrons.
- But to make a complete octet like that of noble gases, each atom most have 8 complete outer most electrons. This is the needed number of electrons. Since there are 5 atoms i.e 4 atoms of chlorine and 1 atom of Silicon, the needed electrons will be 5x8 = 40 electrons.
Learn more:
lewis structure : brainly.com/question/6215269
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Answer:
0.26×10²³ molecules
Explanation:
Given data:
Volume of gas = 1.264 L
Temperature = 168°C
Pressure = 946.6 torr
Number of molecules of gas = ?
Solution:
Temperature = 168°C (168+273= 441 K)
Pressure = 946.6 torr (946.6/760 = 1.25 atm)
Now we will determine the number of moles.
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
n = PV/RT
n = 1.25 atm ×1.264 L / 0.0821 atm.L/ mol.K ×441 K
n = 1.58 /36.21 /mol
n = 0.044 mol
Now we will calculate the number of molecules by using Avogadro number.
1 mol = 6.022×10²³ molecules
0.044 mol × 6.022×10²³ molecules/ 1mol
0.26×10²³ molecules
Answer:
C. 11 moles of N2O
Explanation:
A. CO2 exists as a molecular compound. The number of atoms present = 1 atom of Carbon and 2 atoms oxygen = 3 atoms * 9 = 18 atoms
B. Xe exists as an atom. Number of atoms present = 10 * 1 atom = 10 atoms
C. N20 contains 3 atoms; 2 atoms of Nitrogen and 1 atom of oxygen.
Number of atoms present = 3 * 11 = 33 atoms
D. CO contains 2 atoms, 1 each of carbon and oxygen.
Number of atoms present = 12 * 2 = 24 atoms
They use sequencing technology
