We are going to use this equation:
ΔT = - i m Kf
when m is the molality of a solution
i = 2
and ΔT is the change in melting point = T2- 0 °C
and Kf is cryoscopic constant = 1.86C/m
now we need to calculate the molality so we have to get the moles of NaCl first:
moles of NaCl = mass / molar mass
= 3.5 g / 58.44
= 0.0599 moles
when the density of water = 1 g / mL and the volume =230 L
∴ the mass of water = 1 g * 230 mL = 230 g = 0.23Kg
now we can get the molality = moles NaCl / Kg water
=0.0599moles/0.23Kg
= 0.26 m
∴T2-0 = - 2 * 0.26 *1.86
∴T2 = -0.967 °C
Answer:
protons plus neutrons
Explanation:
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.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons.
The sum of neutrons and protons is the mass number of an atom.
Mass number = number of protons + number of neutrons
while the number of protons or number of electrons is the atomic number of an atom.
Answer:
The order would be: X-Rays, Visible Light, and Infrared Waves.
X-Rays have the shortest wavelength out of all three, then Visible Light, and Infrared Waves have the longest wavelength of the three.
Explanation:
So basically, the LONGER the wavelength, the lower the energy. and the SHORTER the wavelength, the higher the energy. For example, Radio waves are the WEAKEST out of all the types of waves because they have the LONGEST wavelengths. Gamma Rays are the STRONGEST out of all the types of waves because they have the SHORTEST wavelengths. So Radio Waves have the lowest energy, and Gamma Rays have the highest energy.
Here is a list of all the types of waves in order from shortest wavelength to longest wavelengths:
Gamma Rays (Shortest Wavelengths, High Energy), then X-Rays would be the second strongest, then Ultraviolet waves, then Visible Light, then Infrared waves, then Microwaves, and lastly Radio Waves (Longest Wavelengths, Low Energy).
Answer:
a lot that's why it's really hot
Question #1
Potasium hydroxide (known)
volume used is 25 ml
Molarity (concentration) = 0.150 M
Moles of KOH used
0.150 × 25/1000 = 0.00375 moles
Sulfuric acid (H2SO4)
volume used = 15.0 ml
unknown concentration
The equation for the reaction is
2KOH (aq)+ H2SO4(aq) = K2SO4(aq) + 2H2O(l)
Thus, the Mole ratio of KOH to H2SO4 is 2:1
Therefore, moles of H2SO4 used will be;
0.00375 × 1/2 = 0.001875 moles
Acid (sulfuric acid) concentration
0.001875 moles × 1000/15
= 0.125 M
Question #2
Hydrogen bromide (acid)
Volume used = 30 ml
Concentration is 0.250 M
Moles of HBr used;
0.25 × 30/1000
= 0.0075 moles
Sodium Hydroxide (base)
Volume used 20 ml
Concentration (unknown)
The equation for the reaction is
NaOH + HBr = NaBr + H2O
The mole ratio of NaOH : HBr is 1 : 1
Therefore, moles of NaOH used;
= 0.0075 moles
NaOH concentration will be
= 0.0075 moles × 1000/20
= 0.375 M
