Answer:
(a). 4°C, (b). 2.4M, (c). 11.1 g, (d). 89.01 g, (e). 139.2 g and (f). 58 g/mol.
Explanation:
Without mincing words let's dive straight into the solution to the question.
(a). The freezing point depression can be Determine by subtracting the value of the initial temperature from the final temperature. Therefore;
The freezing point depression = [ 1 - (-3)]° C = 4°C.
(b). The molality can be Determine by using the formula below;
Molality = the number of moles found in the solute/ solvent's weight(kg).
Molality = ( 11.1 / 58) × (1000)/ ( 90.4 - 11.1) = 2.4 M.
(c). The mass of acetone that was in the decanted solution = 11.1 g.
(d). The mass of water that was in the decanted solution = 89.01 g.
(e). 2.4 = x/ 58 × (1000/1000).
x = 2.4 × 58 = 139.2 g.
(f). The molar mass of acetone = (12) + (1 × 3) + 12 + 16 + 12 + (1 x 3) = 58 g/mol.
Answer:
Explanation:
The pressure is constant, so we can use Charles' Law to calculate the volume.
Data:
V₁ = 693 mL; T₁ = 45 °C
V₂ = ?; T₂ = 150 °C
Calculations:
(a) Convert temperature to kelvins
T₁ = ( 45 + 273.15) = 318.15 K
T₂ = (150 + 273.15) = 423.15 K
(b) Calculate the volume
I am pretty sure it is density
Answer:
Explanation:
Given reaction
N₂H₄ + O₂ ⇒ N₂ + 2H₂O ΔH₁ = -543 KJ ---------- ( 1 )
2H₂ + O₂ ⇒ 2H₂O ΔH₂ = -484 KJ ---------- ( 2 )
N₂ + 3 H₂ ⇒ 2NH₃ ΔH₃ = -92 KJ -----------( 3 )
( 1 ) - ( 2 ) +( 3 )
N₂H₄ + O₂ - 2H₂ - O₂ +N₂ + 3 H₂ ⇒ N₂ + 2H₂O - 2H₂O +2NH₃
ΔH = -543 + 484 -92 = -151 KJ
N₂H₄ + H₂ ⇒ 2NH₃ ΔH = -151 KJ .
2NH₃ ⇒ N₂H₄ + H₂ ΔH = + 151 KJ
Answer:
Most of the mass of an atom comes from the electron cloud.
Explanation:
All options are correct except,
Most of the mass of an atom comes from the electron cloud. Because,
Most of mass comes from nucleus in which protons and neutrons are present.
The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.
Symbol= e-
Mass= 9.10938356×10-31 Kg
It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties
While neutron and proton are present inside the nucleus. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.
Symbol of proton= P+
Symbol of neutron= n0
Mass of proton=1.672623×10-27 Kg
Mass of neutron=1.674929×10-27 Kg
An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
