Answer:
a chemical change is when the substance turns into a new substance and can not be changed back into its original form
Explanation:
The total reaction energy calculated by reactant bond energy - product
bond energy
The reactant bond energy is usually higher than that of the product bond
energy. This is as a result of the bonds in the product having higher bond
energy than the reactants.
<h3>What is Total reaction energy?</h3>
The total reaction energy is therefore calculated by subtracting the product
bond energy from the reactant bond energy so as to know the net energy
which was used in the reaction.
Read more about Reaction energy here brainly.com/question/24722308
Answer:
23.5 degrees
Explanation:
Today, the Earth's axis is tilted 23.5 degrees from the plane of its orbit around the sun. But this tilt changes. During a cycle that averages about 40,000 years, the tilt of the axis varies between 22.1 and 24.5 degrees. Because this tilt changes, the seasons as we know them can become exaggerated.
Answer:
The density of gallium would be greater than aluminium and boron.
Explanation:
Density:
Density is equal to the mass of substance divided by its volume.
Units:
SI unit of density is Kg/m3.
Other units are given below,
g/cm3, g/mL , kg/L
Formula:
D=m/v
D= density
m=mass
V=volume
Symbol:
The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.
As we move down the group densities increases because larger increase in mass occur with increase ion volume and greater sizes of elements down the group.
The boron, aluminium and gallium present in group thirteen. Boron is present in period two aluminium is present in period three and gallium is present in period four. So, atomic number of gallium is greater than boron and aluminium and it is appear as we move down the group. that's why gallium has larger size and greater value of density then boron and aluminium.
The value of density of gallium is 5.904 g/cm³.
