948 or 9.48 x 10^2
There are two sets of rules for significant figures
• One set for addition and subtraction
• Another set for multiplication and division
You used the set for multiplication and division.
This problem involves addition and subtraction, and the rule is
The number of places after the decimal point in the answer must be <em>no greater than the number of decimal places in every term</em> in the sum.
Thus, we have
78.9
+890.43
-21.
= 948.33
The "21" term has the fewest digits after the decimal point (none), so the answer must have no digits after the decimal point.
To the correct answer is 948 = 9.48 x 10^2. It has three significant figures.
1 mole contains = 6.02x10^23 atoms. 0.31mole contains = 0.31x6.02x10^23 = 1.8662x10^23.
Since the half-reaction is occurring in a basic solution, add 32OH− to each side of the equation to eliminate the H+ ions.
P₄ +16H₂O + 32OH⁻ ⟶ 4PO₃⁻⁴ + 32H⁺ +32OH⁻
Final reaction :
P₄ + 32OH⁻ ⟶ 4PO₃⁻⁴ + 16H₂O + 20e⁻
A half reaction is either the oxidation or reduction reaction component of a redox reaction. A half reaction is obtained by considering the change in oxidation states of individual substances involved in the redox reaction.
The concept of half-reactions is used to describe what occurs in an electrochemical cell, such as a Galvanic cell battery. Half-reactions can be written to describe both the metal undergoing oxidation (known as the anode) and the metal undergoing reduction (known as the cathode).
Half-reactions are often used as a method of balancing redox reactions. For oxidation-reduction reactions in acidic conditions, after balancing the atoms and oxidation numbers, one will need to add H+ ions to balance the hydrogen ions in the half reaction.
For oxidation-reduction reactions in basic conditions, after balancing the atoms and oxidation numbers, first treat it as an acidic solution and then add OH- ions to balance the H+ ions in the half reactions (which would give H2O).
Learn more about Half reactions here : brainly.com/question/2491738
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Answer:
7.03 g
Explanation:
Step 1: Write the balanced synthesis reaction
N₂(g) + 3 H₂(g) ⇒ 2 NH₃(g)
Step 2: Calculate the moles corresponding to 32.5 g of N₂
The molar mass of N₂ is 28.01 g/mol.
32.5 g × 1 mol/28.01 g = 1.16 mol
Step 3: Calculate the number of moles of H₂ needed to react with 1.16 moles of N₂
The molar ratio of N₂ to H₂ is 1:3. The moles of H₂ needed are 3/1 × 1.16 mol = 3.48 mol.
Step 4: Calculate the mass corresponding to 3.48 moles of H₂
The molar mass of H₂ is 2.02 g/mol.
3.48 mol × 2.02 g/mol = 7.03 g
