Answer:
A) False
B) True
C) True
D) True
Explanation:
A) False. If the charge of the atom is +2 means that you have two protons more than number of electrons. If you have 36 electrons you must have <em>38 protons.</em> Also, the electrons are not in the nucleus.
B) True. The isotope of X contains 38 protons, two more than the electron number.
C) True. The mass number is the number of protons + number of neutrons.
If the mass number is 79 and there are 38 protons you must have 41 neutrons.
D) True. You can now the identity of the atom with the number of protons that is the same than atomic number. The strontium, Sr, is the atom with 38 as atomic number.
I hope it helps!
Answer:
Energy is released in this reaction possibly in the form of heat thus it is an exergonic and or exothermic reaction.
Answer:
14175 j heat released.
Explanation:
Given data:
Mass of aluminium = 350.0 g
Initial temperature = 70.0°C
Final temperature = 25.0°C
Specific heat capacity of Aluminium = 0.9 j/g.°C
Heat changed = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
Heat change:
ΔT = Final temperature - initial temperature
ΔT = 25.0°C - 70°C
ΔT = -45°C
Q = m.c. ΔT
Q = 350 g × 0.9 j/g.°C × -45°C
Q = -14175 j
You just need to multiply the terms and transform to kj by dividing by 1000
1) 10.4kj
2) 14.5 kj
3) 44.8 kj
4) 1.04 kj
and there you go.
Answer : The correct option is C.
Explanation :
Chemical change : It is defined as a change in which a new compounds are formed by the chemical reaction. Changes occurs in their chemical composition and properties.
The molecular structure of a substance changes in a chemical reaction is a chemical change.
- Change in molecular structure means that there is a breaking and formation of bonds in a molecule.
The example of chemical change in terms of change in molecular structure is the reaction of hydrogen with oxygen.
The reaction of hydrogen with oxygen is,
In this reaction, the H-H bond is break and O-H bond is form.
