Physical changes occur when the properties of a substance are retained and/or the materials can be recovered after the change. Chemical changes involve the formation of a new substance. Formation of a gas, solid, light, or heat are possible evidence of chemical change.
Answer:
2NaCl+H2SO4-->Na2SO4+2HCl
Explanation:
There are two Na on the right, so put a 2 in front of NaCl on the left. This makes 3 Cl also, so put a 2 in front of HCl on the right. There are already 2 H on the left, so the equation is balanced.
Answer:
22.44°C will be the final temperature of the water.
Explanation:
Heat lost by tin will be equal to heat gained by the water
Mass of tin = 
Specific heat capacity of tin = 
Initial temperature of the tin = 
Final temperature = 
=T
Mass of water= 
Specific heat capacity of water= 
Initial temperature of the water = 
Final temperature of water = =T
On substituting all values:
we get, T = 22.44°C
22.44°C will be the final temperature of the water.
Answer:
J.J. Thomsons model represents the structure of an atom.
J.J. Thomson's experiments with cathode-ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged particles.
