Answer:
Water boils - physical change
Salt dissolves in water- chemical change
Milk turns sour- chemical change
metal rusts - chemical change
Explanation:
A chemical change refers to changes that are irreversible and the process involves the evolution of heat along with the formation of a new substance, examples include;Salt dissolves in water, Milk turns sour, metal rusts etc
The boiling of water is a physical change. The water can be cooled and the vapour condensed,hence, the boiling of water is a physical change.
Physical changes are easily reversible and no new substance is formed.
Answer:
The statements which are true among these are: (a),(b) and (c) because,
(a) The simplest organic compounds which contains only carbon and hydrogen atoms are called hydrocarbons.
(b) The IUPAC naming of organic compounds have some rules for the naming of compounds, which consists of
- Finding the longest chain present in the compound called parent chain.
- A prefix for any substituent attach to the parent chain.
And lastly a suffix for the type of bond that molecule have.
(c) Isomers are the compound which same same molecular formula but different arrangement of molecules, due to this different arrangement they have different physical and chemical properties.
The balanced equation for the ionization of the weak base pyridine,C5H5N in water, H2O
C_5H_5N ( aq.) + H2O ( l) ---------> C5H5NH+ (aq.) + OH- (aq.)
<h3>What is the balanced equation for the ionization?</h3>
Generally, Pyridine is characterized by a ring structure, in this characteristic ring structure N is sp2 hybridized, hence creating a lone pair present on N so s - character is more, as well as lone pair, is present.
Therefore, Considering The following functions of the equation:weak base pyridine,C5H5N in water, H2O
We write the balanced equation for the ionization as
C_5H_5N ( aq.) + H2O ( l) ---------> C5H5NH+ (aq.) + OH- (aq.)
Read more about Chemical Reaction
brainly.com/question/11231920
Answer:
ΔH = - 272 kJ
Explanation:
We are going to use the fact that Hess law allows us to calculate the enthalpy change of a reaction no matter if the reaction takes place in one step or in several steps. To do this problem we wll add two times the first step to second step as follows:
N2(g) + 3H2(g) → 2NH3(g) ΔH=−92.kJ Multiplying by 2:
2N2(g) + 6H2(g) → 4NH3(g) ΔH=− 184 kK
plus
4NH3(g) + 5O2(g) → 4NO(g) +6H2O(g) ΔH=−905.kJ
__________________________________________________
2N2(g) + 6H2(g) + 5O2(g)→ 4NO(g) + 6H2O(g) ΔH = (-184 +(-905 )) kJ
ΔH = -1089 kJ
Notice how the intermediate NH3 cancels out.
As we can see this equation is for the formation of 4 mol NO, and we are asked to calculate the ΔH for the formation of one mol NO:
-1089 kJ/4 mol NO x 1 mol NO = -272 kJ (rounded to nearest kJ)
The density of ethylene glycol is: D = 1.11 g/mL
D = m / V
and V = 358 mL
m = D * V
m = 1.11 g/mL * 358 mL
m = 397.38 g
Answer:
Mass is 397.38 g.
