3. A
4. B
5. A
6. E
7. A
8. C
9. A
10. B
Some of these were guesses but they were educated guesses. Best of luck. If some of them are wrong I am sorry. <span />
The on that is considered a physical change is : A. Sawing a piece of wood in half
When you cut a piece of wood, the chemical compound within the wood will not change at all, which mean that it's a physical change
hope this helps
Answer:
2Fe + 8HCl =2 HFeCl4 + 3H2
Explanation:
Fe + HCl = HFeCl4 + H2
1Fe 1Fe
1H 3H
1Cl 4CL
2Fe + 8HCl =2 HFeCl4 + 3H2
2Fe 2Fe
8H 8H
8Cl 8CL
The volume of HCOOH is 0.003 Lt and the volume of HCOONa is 0.017 LT.
Explanation:
For acidic buffer
PH = Pka + log
4.25 = 3.75 + log
log = 0.75
log = 5.62 is considered as equation 1.
Let V₁ ml of HCOOH and V₂ml of HCOONA was mixed and the final volume is 100 ml .
V₁ *0.5 + V₂ *0.5 =0.1 * 100
V₁+V₂ = = 20 is the second equation.
Now concentration of salt and acid are
V₂ [salt] = 0.5/100 and v₁ [acid] = 0.5/100
by substituting these in equation 1 we get,
= 5.62
V₂ = V₁ * 5.62 is the 3 rd equation
by solving 2 and 3 we get,
5.62 V₁ + V₁ = 20
= 6.62 V₁ = 20
V₁ = 3.02 ml
V₁ = 0.003 LT
V₂ = V₁ * 5.62
V₂ = 0.017 LT
Hence the volume of HCOOH is 0.003 Lt and the volume of HCOONa is 0.017 LT.
The answer is C because by process of elimination, we know that it’s an attractive force and we know that electrons can be found quite far from the nucleus depending on the amount of energy they have.