Isotopes are atoms of the same element that differ in the number of neutrons.
Remember that all the atoms of an element have the same number of protons. So the only difference between isotopes of an element is the number of neutrons.
86 Sr means that the mass number of this isotope is 86. Also, remember that the mass number is the number of protons plus the number of neutrons.
87 Sr means that the mass number of this isotope is 87.
So, 86 Sr and 87 Sr differ 1 neutron.
Answer: 1 neutron
In the U.S.A, it is the Mississippi River Basin. But then there is the Gulf of Mexico.
Answer:
See explanation
Explanation:
Matter may exist in three phases; solid, liquid and gas. The state in which matter exists depends on the extent of intermolecular forces operating in the substance.
In solid particles, the molecules that compose the solid are close together because the molecules of a solid do not move from place to place but they continue to vibrate about their fixed position.
For liquids, the molecules that compose a liquid are in random motion but are less energetic than molecules of a gas.
In gases, the molecules are not held together at all. The molecules of a gas have the highest degree of freedom. They move from one point another at a high velocity.
Hence, the order of increasing degree of movement of the particles in different states of matter = solids<liquids< gases.
Solids have well arranged particles, the molecules of a liquid are a little more disorderly than liquid particles while gas particles are the most disorderly of all the states of matter.
<u>Answer:</u> The 
for the reaction is -1835 kJ.
<u>Explanation:</u>
Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.
According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.
The given chemical reaction follows:
The intermediate balanced chemical reaction are:
(1) 
( × 4)
(2) 
The expression for enthalpy of the reaction follows:
![\Delta H^o_{rxn}=[4\times (-\Delta H_1)]+[1\times \Delta H_2]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5B4%5Ctimes%20%28-%5CDelta%20H_1%29%5D%2B%5B1%5Ctimes%20%5CDelta%20H_2%5D)
Putting values in above equation, we get:
Hence, the for the reaction is -1835 kJ.
