Answer:
Molecules that contain dipoles are called polar molecules and are very abundant in nature. For example, a water molecule (H2O) has a large permanent electric dipole moment.
so it is (D). H2O
Explanation:
The volume of the substance is 61.4 litres.
Explanation:
Specific density is the ratio of density of a substance at a given temperature with the density of reference substance.
Data given:
mass = 750 grams
specific gravity = 12.2
volume=?
The formula to be used:
Specific gravity = 
suppose the other substance is water so its density is 1g/ml at 4 degrees
Putting the values to the equation:
density of the object = 1 x12.2
density of the substance = 12.2
Now using the formula:
density = 
putting the values in the equation:
volume = 
= 61.4ml is the volume of the substance.
Answer:
Nitrogen reacts with oxygen to form a number of nitrogen oxides. It exhibits different oxidation states in its oxides, ranging from +1 to +5. Oxides of nitrogen having nitrogen in the higher oxidation state are more acidic than that in lower oxidation state. Nitrogen oxides are critical components of photochemical smog. They produce the yellowish-brown colour of the smog. In poorly ventilated situations, indoor domestic appliances such as gas stoves and gas or wood heaters can be significant sources of nitrogen oxides.
Following are the harmful effects caused by the oxides of nitrogen
Nitrogen oxides causes irritation in mucous membrane.
Large concentrations of Nitrogen oxide causes lungs problems in humans
It causes injuries to vegetation by damaging leaves.
Nitrogen oxide oxidizes Hydrocarbons in the presence of sunlight, which causes eye irritation, asthama attacks, nasal and throat infections.
NO: sharp, sweet-smelling, colourless gas. Melting point: -163.6°C. Boiling point: -151.8°C. Relative Density: 1.04 (air = 1) NO2: reddish-brown gas with irritating odour
Some physical properties change, but the substance keeps its identity.
When dealing with these kind of questions, understand that the keyword here is physical change. Thus, all options that says no physical properties change are WRONG. So this leaves us with only 2 answers left. However, this is a physical change, no chemical change. Thus, the substance will keep its identity and not change.
Answer:
identify the atoms on each side.
Count the atoms on each side.
Use coefficients to increase the atoms on each side.
Check to make sure you have the same number of each type of atom on each side.
Explanation:
The concept behind balancing chemical equations is to ensure that they comply with the law of conservation of matter. This helps to make chemical equations quantitatively meaningful.
- First, identify the atoms on each side of the expression.
- Then count these atoms.
- Assign appropriate numeric coefficient to the species.
- Then check to make sure there are equal number of each type of atoms on each side.
The subscript of the formula must not be changed in an attempt to balance a chemical equation.
