Answer:
Explanation:
They gave us the masses of two reactants and asked us to determine the mass of the product.
This looks like a limiting reactant problem.
1. Assemble the information
We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 239.27 32.00 207.2
2PbS + 3O₂ ⟶ 2Pb + 2SO₃
m/g: 2.54 1.88
2. Calculate the moles of each reactant
3. Calculate the moles of Pb from each reactant
4. Calculate the mass of Pb
The joules required to heat 2L of water in a pot from 20 c to the boiling point of water is calculated using the following formula
Q= MC delta T
M = mass = density x volume( 2 x 1000= 2000ml)
M = 1g/ml x2000 ml = 2000g
C = specific heat capacity = 4.18 g/c
delta T = change in temperature = 100 c ( boiling point of water) - 20 c = 80 c
Q is therefore = 2000 g x 4.18 j/g c x 80c = 668800j
It’s considered the “universal solvent” because water dissolves more substances than any other chemical.
C. the substance only changed form or appearance
the substance changes at a chemical level, not just in appearance
Answer:
KBr: strong ion-ion forces
Explanation:
Ionic compounds are non-molecular species. During melting they require a lot of energy input so that the strong ionic bonds that constitute the electrostatic lattice be disrupted. It thus requires very high temperatures. This is indicative of a very strong ion-ion electrostatic interaction which is typical of ionic bonds and results in high melting points of ionic solids.
Hence, the process of melting an ionic solid needs the addition of a large amount of energy in order to break all of the ionic bonds in the crystal.
On the other hand, Br2 is a covalent molecular specie. Most covalent compound have low melting points since their molecules are mostly held together only by weak van der waals forces.
