Answer:
-1.82 °C
Explanation:
Step 1: Given data
- Mass of NaCl (solute): 33.9 g
- Mass of water (solvent): 578 g = 0.578 kg
- Freezing point depression constant for water (Kb): -1.82 °C/m
Step 2: Calculate the molality of the solution
We will use the following expression.
m = mass of solute / molar mass of solute × kg of solvent
m = 33.9 g / 58.44 g/mol × 0.578 kg
m = 1.00 m
Step 3: Calculate the freezing point depression (ΔT)
The freezing point depression is a colligative property that, for a non-dissociated solute, can be calculated using the following expression:
ΔT = Kb × m
ΔT = -1.82 °C/m × 1.00 m
ΔT = -1.82 °C
Answer:
the weight of products is is equal the weight of the wood plus the weight of oxygen that was used to burn that wood, so weigh of the product is greater than 10 kilograms.
Explanation:
Conservation of mass (mass is never lost or gained in chemical reactions), during chemical reaction no particles are created or destroyed, the atoms are rearranged from the reactants to the products.
In this example wood (mostly carbon) and oxygen are reactants and carbon dioxide (mostly) is product of reaction.
Answer:
Mass number is defined as the number of protons plus the number of neutrons.
Explanation:
Every atom of an element have proton(s), neutron(s) and electron(s). The proton number of an element is the atomic number of that element. For an electronically neutral atom the proton number is equal to the electron numbers. The neutron and the proton contributes to the mass of every atom. The electron is more active when atoms are bonding.
Mass number of an element is the number of proton plus the number of neutron.
Atomic number of an atom is the number of proton present, so it can never be atomic number.
Isotopy talks about same element having different number of neutron but same number of protons in each atom. Example is hydrogen that exist as protium, deuterium and tritium. It cannot be isotopic number.
Ionic number talks about elements that possess a charge. The elements have been ionized.
The answer is Mass number because the sum of proton number and neutron number is equals to mass number.
Answer:
Dipole-dipole attractions
Explanation:
The Cl atom is more electronegative than H, so it attracts the electrons in the H-Cl bond more to itself.
The Cl end of the molecule becomes partially negative (δ-), and the H end becomes more positive (δ+). This separation of charge is called an electric dipole,
When two HCl molecules are near each other, they arrange themselves so that the negative and positive ends of the dipoles line up and attract the two molecules together.
