3 years ago

Which statement best describes the difference between a physical change and a chemical change

1 answer:

6 0

Physical change happens alone without adding chemical but by doing things but you add chemicals and other things to have chemical change

You might be interested in

When a substance melts the kinetic energy

aliina [53]

Answer:

C stays The same.

Is the answer.

8 0

3 years ago

Read 2 more answers

The light produced by the electron in strontium has a wavelength of 608 nm. How much energy must be added to strontium to get it

liq [111]

According to Einstein the energy of photon is given by the equation,

E = hν = h . c/λ

where h is Planck's constant, c is the speed of light, ν is the frequency of light and λ is the wavelength of light.

Given, wavelength = 608 nm = 608 x 10⁻⁹ m

Conversion factor: 1 nm = 10⁻⁹ m

c = 3 x 10⁸ m/s

h = 6.626× 10⁻³⁴ J.s

Substituting the data into the equation we get,

E = h . c/λ

E = 6.626× 10⁻³⁴ J.s x (3 x 10⁸ m/s) / 608 x 10⁻⁹ m

E = 3.27 x 10⁻¹⁹J

3.27 x 10⁻¹⁹J energy must be added to strontium to get it to produce 608 nm wavelength.

6 0

4 years ago

Iron crystallizes in a body-centered cubic unit cell. The edge length of this cell is 287 pm. Calculate the density of iron in g

Jlenok [28]

Answer:

Density = 7.87 grams per mL

Explanation:

Density is given by the formula:

$d=\frac{Z\times M}{a^{3}\times N_a}$

where

Z = effective number of atoms in one unit cell.

M = Molecular mass of the substance

a = edge length of unit cell

Na = Avogadro number = 6.022×10²³

In this case:

Z=2 as it is body-centered type unit cell

M = 56 g per mole for iron

a = 287 pm = $287\times10^{-10}\ cm$

Substituting the above values in the density formula we get:

$d=\frac{2\times56}{(287\times10^{-10})^{3}\times6.022\times10^{23}}=7.87\ g\ per\ ml$

Density of iron is 7.87 grams per mL.

7 0

3 years ago

The heaviest commonly used United States coin is the half dollar, which has a mass of 11.340g. The lightest United States coin i

Kruka [31]

Answer:

13.6×10^3

Explanation:

11.340+2.268= 13.608

7 0

4 years ago

Which phrase best indicates the appropriate<br> audience?

kotegsom [21]

I don’t know the answer choices

8 0

3 years ago