Answer:
2 and 4
Explanation:
The rest of the changes are chemical. 1 has a chemical reaction happen which makes light sticks glow. 3 is because browning the meat actually causes some new compounds to form and cause caramelization.
For 2, the oxygen is simply heating up and expanding which pops the balloon. 4 is just a phase change of water vapor to liquid water.
Answer:
B. The number of atoms in a molecular formula is always greater than the number of atoms in an empirical formula.
Explanation:
It is not always true that the number of atoms in a molecular formula is always greater than the number of atoms in an empirical formula.
The chemical formulae of a compound are of two main types;
- The empirical formula is that which expresses the composition of a compound in the simplest whole number ratio.
- The molecular formula shows the actual ratio of the atoms in a compound.
Sometimes the number of atoms in the molecular and empirical formula can be the same.
Also, the number of atoms in the molecular formula is always greater than that of the empirical formula when they are not the same.
To solve this problem, separate it into chunks that you know. You know that there are 2.54 centimeters in 1 inch. You know that there are 100 centimeters in 1 meter. You know that there are 1000 meters in a kilometer. Therefore, we'll convert in this order: 1) from kilometers to meters, 2) from meters to centimeters, and 3) from centimeters to inches.
1) 1km × 1000m/1km
= 1000m
2) 1000m × 100cm/1m
= 100000cm
3) 100000cm × 1in/2.54cm
≈ 39370in
So, there are approximately 39370 inches in a kilometer.
Answer:
Homologous series is defined as a systematic order of structurally similar organic compound containing same functional group in their family and two adjacent members differ in their molecular formula by -CH2 unit.
Characteristics:
1.Various members of homologous series contain same functional group.
2.Various members of homologous series can be represented by common formula.
3. All members of a homologous series have almost similar chemical properties.
4. All members have common method of preparation.
5.Two successive members of homologous series have different chain length or difference in their molecular formula by -CH2 unit.
6.The members of homologous series show different physical properties.
Faster molecules have fewer collisions than slower molecules is True about molecular speed.
<h3>What is Molecular speed?</h3>
Molecular speed refers to the average distance gases or molecules travelled atca particular time rate.
It is valid in ideal gas, where the molecules do not interact with others.
Average molecular speed = Square root (3 (ideal gas constant) * (Temperature)/m)
Therefore, Faster molecules have fewer collisions than slower molecules is True about molecular speed.
Learn more about molecular speed from the link below.
brainly.com/question/14327643
