In 1869 he published a table of the elements organized by increasing atomic mass.
Mendeleev is called the "father of the modern periodic table
stated that if the atomic weight of an element caused it to be placed in the wrong group, then the weight must be wrong. (He corrected the atomic masses of Be, In, and U)
was so confident in his table that he used it to predict the physical properties of three elements that were yet unknown.
After the discovery of these unknown elements between 1874 and 1885, and the fact that Mendeleev's predictions for Sc, Ga, and Ge were amazingly close to the actual values, his table was generally accepted.
However, in spite of Mendeleev's great achievement, problems arose when new elements were discovered and more accurate atomic weights determined.
STOP DELETING MY COMMENTS PEOPLE PLEASE!!!!!!!!!
Probably true because chemicals do control weed and it hurts the environment.
prince Henry is your answer (:
Answer:
(NH₄)₃PO₄ (l) + Al(NO₃)₃(l) -----------→ AlPO₄(l) + 3NH₄NO₃(l)
Explanation:
Data Give:
Reaction between ammonium phosphate solution and solution of aluminum nitrate
- Write a balanced chemical equation
Details:
To write a balanced chemical equation we have to know formula units of compounds or molecules
Formula units
ammonium phosphate : (NH₄)₃PO₄
aluminum nitrate: Al(NO₃)₃
ammonium nitrate: NH₄NO₃
Now to write a chemical equation
- we have to write the chemical formulas or formula unit of each compound
- write the reactant on left side of the arrow
- write the product on the right side of the arrow
- put a plus sign in 2 reactants and products on each side of the arrow
- balance the equation by putting coefficient with compound formula
- write the phase symbols on the right corner of the compound formula in brackets
So the Reaction will be
(NH₄)₃PO₄ + Al(NO₃)₃ -----------→ AlPO₄ + NH₄NO₃
Now balance the Chemical equation
(NH₄)₃PO₄ + Al(NO₃)₃ -----------→ AlPO₄ + 3NH₄NO₃
Now write the phase Symbols
(NH₄)₃PO₄ (l) + Al(NO₃)₃(l) -----------→ AlPO₄(l) + 3NH₄NO₃(l)
all compounds in the reaction are in liquid form and soluble in water
*** Note:
There is no aluminum nitrite in chemicals formulas
Also ammonium nitrite can not be used in pure isolated form due to its highly instability
The correct answer is + 32.5 J because heat is absorbed here by copper not evolved also after calculation we will find the H value is positive, lets calculate it:
H = m C Δt where:
m = 10 g
C = 0.13 J/g.°C
Δ t = final temperature - initial temperature = 50 - 25 = + 25 °C
so H = 10 x 0.13 x (+25) = + 32.5 J
