Answer:
When a copper is drawn into wire the only change that occurs is change in its shape and size no change will take place into its composition that is the wires are still possessing the properties of copper metal. Thus, a physical change takes place when copper is drawn into wire.
Answer:
The correct answer to the following question will be "4.08 × 10⁻¹⁹ Joule".
Explanation:
Given:
Wavelength, λ = 486.0 nm
As we know,

On putting the estimated values, we get
⇒ 
⇒ 
∴ 1 ev = 1.6 × 10⁻¹⁹ J
Now,
Energy, 
⇒ 
Answer:

Explanation:
Given that:

From equation (3) , multiplying (-1) with equation (3) and interchanging reactant with the product side; we have:

Multiplying (2) with equation (4) ; we have:

From equation (1) ; multiplying (-1) with equation (1); we have:

From equation (2); multiplying (3) with equation (2); we have:

Now; Adding up equation (5), (6) & (7) ; we get:



<u> </u>

<u> </u>
<u />
(According to Hess Law)


Answer:
Yes it is B,D.
Explanation:
Each box represents an element and contains its atomic number, symbol, average atomic mass, and (sometimes) name. The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups.