The given question is incomplete. the complete question is:
The world burns the fossil fuel equivalent of approximately 
kg of petroleum per year. Assume that all of this petroleum is in the form of octane. Calculate how much CO2 in kilograms is produced by world fossil fuel combustion per year.( Hint: Begin by writing a balanced equation for the combustion of octane.)
Answer: 
Explanation:
Combustion is a chemical reaction in which hydrocarbons are burnt in the presence of oxygen to give carbon dioxide and water.
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
To calculate the moles :
According to stoichiometry :
As 2 moles of octane give = 16 moles of 
Thus 
of octane give =
of
Mass of 
Thus of is produced by world fossil fuel combustion per year.
Answer:
CH3 - CH2 - NH - C(CH3)3
Explanation:
The 1HNMR is the acronym for Proton nuclear magnetic resonance and it is used in chemistry or Chemical laboratory for the analysis and identification of compounds.
In order to be able to answer the question accurately you have to have the tables containing all the values for chemical shift. The Chemical shift is measured in ppm and it occur due to Resonance frequency variation.
From the table, a singlet at 1.15 ppm (9H) is - C(CH3)3.
A singlet at d 0.9 ppm (1H) shows the presence of a secondary amine group, that is -R2NH group.
A triplet at 1.10 ppm (3H) shows that we have;
CH3- CH2-
A quartet at 2.6 ppm (2H) shows that we have;
-CH2 - CH3.
Therefore, joining all together we have;
CH3 - CH2 - NH - C(CH3)3.
Kindly check attached file for the picture of the structure.
Properties of matter can be broadly classified into two categories:
Physical properties which usually involve a change in the state of matter and Chemical properties which involve a change in the chemical composition of matter.
Now, physical properties can be further classified as:
Extensive: these depend on the amount of the substance, eg: mass, volume
Intensive: these do not depend on the amount of the substance eg: density, color, melting point, boiling point
Here we are given a 5.0 g and 1 cm3 silver cube :
Therefore:
Extensive properties are-
1) Mass of silver = 5.0 g
2) Volume of silver = 1 cm3
Intensive properties are:
1) Density of silver = mass/volume = 5.0 g/ 1 cm3 = 5.0 g/cm3
2) Melting point of silver = 962 C
3) Color = white/gray
Answer: m = 50 g ZnSO4
Explanation: First is convert the moles of Zn to the moles of ZnSO4 by having their mole ratio which is 2:2 based from the balanced equation. Next is convert the moles of ZnSO4 to mass using its molar mass.
0.311 mole Zn x 2 moles ZnSO4 / 2 moles Zn
= 0.311 moles ZnSO4
0.311 moles ZnSO4 x 161 g ZnSO4 / 1 mole ZnSO4
= 50 ZnSO4
