Answer:
1. A state of balance in which the rates of the forward and reverse reactions are equal.
Explanation:
A dynamic equilibrium is like a cycle, the reactants change to products, but the products also change to reactants keeping the amount of each constant.
2. A state of balance in which the forward reaction stops but reverse reaction continues.
In this statement there isnt a equilibrium. The products will change to reactants until the reaction stops.
3. A state of balance in which the forward reaction continues but reverse reaction stops.
Here the reactants will change to products until the reaction stops.
4. A state of balance in which the forward and reverse reactions stop.
In this case the reaction has stopped.
The heat transfer just occurred is mainly conduction.
Conduction happens when two objects are in contact with each other. In the hotter object, the molecules and/or free electrons have a higher kinetic energy, thus they'll travel and collide into other molecules, resulting in spreading the energy to the other object.
The heat transfer happens until thermal equilibrium, where both objects have the same temperature and their molecules have the same kinetic energy rate.
In addition, radiation is also happening since everything that has a higher temperature than the environment is a net emitter. They release electromagnetic waves that turn out to be radiation. These occur even without the presence of air.
Answer:
Mass states that mass is neither created nor destroyed in a chemical reaction or a physical transformation
Explanation:
Energy diagram for and endothermic and exothermic reaction
Explanation:tr
a) Molar mass of HF = 20 g/mol
Atomic mass of hydrogen = 1 g/mol
Atomic mass of fluorine = 19 g/mol
Percentage of an element in a compound:

Percentage of fluorine:

Percentage of hydrogen:

b) Mass of hydrogen in 50 grams of HF sample.
Moles of HF = 
1 mole of HF has 1 mole of hydrogen atom.
Then 2.5 moles of HF will have:
of hydrogen atom.
Mass of 2.5 moles of hydrogen atom:
1 g/mol × 2.5 mol = 2.5 g
2.5 grams of hydrogen would be present in a 50 g sample of this compound.
c) As we solved in part (a) that HF molecules has 5% of hydrogen by mass.
Then mass of hydrogen in 50 grams of HF compound we will have :
5% of 50 grams of HF = 