Answer:
Kb = 0.428 m/°C
Explanation:
To solve this problem we need to use the <em>boiling-point elevation formula</em>:
- <em>Tsolution</em> - <em>Tpure solvent</em> = Kb * m
Where <em>Tsolution</em> and <em>Tpure solvent</em> are the boiling point of the CS₂ solution (47.52 °C) and of pure CS₂ (46.3 °C), respectively. Kb is the constant asked by the problem, and m is the molality of the solution.
So in order to use that equation and solve for Kb, first we <em>calculate the molality of the solution</em>.
molality = mol solute / kg solvent
- Density of CS₂ = 1.26 g/cm³
- Mass of 410.0 mL of CS₂ ⇒ 410 cm³ * 1.26 g/cm³ = 516.6 g = 0.5166 kg
molality = 0.270 mol / 0.5166 kg = 0.5226 m
Now we <u>solve for Kb</u>:
<em>Tsolution</em> - <em>Tpure solvent</em> = Kb * m
- 47.52 °C - 46.3 °C = Kb * 0.5226 m
Answer and Explanation:
Iodine have lower atomic mass than tellurium even though the atomic number of iodine is more than the atomic number of tellurium
This is because the atomic weight of any element is the sum of number of proton and number of neutron, even though the number of proton in iodine is more so but the number of neutron is less as compared to tellurium which makes the tellurium of high atomic mass
Answer:
Atoms are made of protons, neutrons and electrons.
Explanation:
The Dalton's atomic theory was an early attempt at describing the properties of atoms. It stipulated that atoms were the smallest indivisible particle of a substance. Chemical reactions occur as a result of a combination or separation of atoms. Atoms of the same element are exactly alike and differ from atoms of other elements. Atoms can neither be created nor destroyed.
As time went on, modern scientific evidence began to modify the original postulates of the Dalton's atomic theory. It was not postulated in 1805 that atoms were composed of subatomic particles; electrons, neutrons and protons. Dalton's theory held the atom to be 'indivisible'. However in 1897, JJ Thompson discovered the electron. Subsequently, the proton and neutrons were discovered. This shows that the atom in itself consisted of even smaller particles.
The Lewis structure for H₂CO is shown in the attached picture. The central atom is the carbon. However, I'm not sure which bond you're referring to. There can be two answers. The two C-H bonds are sp³ hybridized because it is a single bond. The C=O bond is sp² hybridized because it is a double bond.
1. Answer: C. The objects' temperatures have both changed by the same amount.
Explanation:
An object is said to be in thermal equilibrium when the objects have attained same temperature. Heat transfer from hotter object to colder one in contact takes place until the temperature of the two are equal. It is not necessary that the temperature of both the objects changes by same amount. After attainment of thermal equilibrium, the temperature of the objects stop changing and the tiny particles of the object move at the same rate.
Hence, the objects' temperatures have both changed by the same amount. is not necessarily true for two objects in thermal equilibrium.
2. Answer: C. Objects are made of tiny particles, and their motion depends on the temperature.
Explanation:
Kinetic theory of heat states that the kinetic energy of constituent particles determine the temperature of the object. The statement that best explains this is Objects are made of tiny particles, and their motion depends on the temperature.
