Answer:
Option B is correct.
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. The number of protons or neutrons is the atomic number of an atom while sum of proton and neutrons is the mass number.
The beryllium atom have five neutrons, four protons and four electrons.
The option be is correct model of beryllium because it shows that there are four protons and five neutron in nucleus of beryllium atom and four electrons revolving around the nucleus.
Beryllium is alkaline earth metal.
It is present in group two.
Its atomic number is 4.
its atomic mass is 9 amu.
Answer:
∴ΔH₂ = - 12,258 KJ
Explanation:
Enthalpy:
Enthalpy is a property of a thermodynamic system. Enthalpy of a system is equal to the sum of internal energy of the system and presser times volume of the system.
The heat absorbes or releases in a closed system is the change of enthalpy of the system.
Given reactions are:
Reaction 1: C₃H₈(g)+5O₂(g)→ 3CO₂(g)+4H₂O, ΔH₁= - 2043 KJ
Reaction 2: 6C₃H₈(g)+30 O₂(g)→ 18 CO₂(g)+24 H₂O, ΔH₂=?
Take a look at reaction 1 and reaction 2, the only difference is that 1 molecule of C₃H₈ is combusted in reaction 1 and 6 molecules of C₃H₈ is combusted in reaction 2.
We can think the reaction 2 as occurring 6 different container and each containers contains 1 molecule of C₃H₈. The enthalpy is an extensive property. Total enthapy of the 6 containers is = 6×(-2043 KJ)
= - 12,258 KJ
∴ΔH₂ = - 12,258 KJ
Answer:
A. It is the ratio of the concentrations of products to the concentrations of reactants.
Explanation:
The equilibrium constant of a chemical reaction is the ratio of the concentration of products to the concentration of reactants.
This equilibrium constant can be expressed in many different formats.
- For any system, the molar concentration of all the species on the right side are related to the molar concentrations of those on the left side by the equilibrium constant.
- The equilibrium constant is a constant at a given temperature and it is temperature dependent.
- The derivation of the equilibrium constant is based on the law of mass action.
- It states that "the rate of a chemical reaction is proportional to the product of the concentration of the reacting substances. "
Alexandra requires a total energy of 1350 kcal for the climb
by eating proteins, fats and carbohydrates the amount of calories per gram contributed varies.
Proteins and carbohydrates - 4 calories per gram
fats - 9 calories and gram
This means that by eating the same mass of fats and proteins/ carbohydrats the calories gained from fats is higher.
each bar contains;
<span>50 g of carbohydrates - 4 calories/g x 50 g = 200 calories
10 g of fat - 9 calories/g x 10 g = 90 calories
40 g of protein - 4 calories/g x 40 g = 160 calories
total amount of calories from 1 bar = 200 + 90 + 160 = 450 calories
energy required = 1 350 000 calories
bars required = 1 350 000/450 = 3000
alexandra should consume 3000 bars </span>
The answer is C, i just took the k-12 test~
