Name a substance in the air which makes the surface of limestone change

PLEASE HELP ME! do tectonic plates play a major or minor role in the ROCK CYCLE

dexar [7]

Tectonic plates are key to the rock cycle as their motions result in processes that are important to the rock cycle, therefore they play a major role in the rock cycle

4 0

2 years ago

Determine whether the following statements describe chemical or physical properties: (a) Oxygen gas supports combustion. (b) Fer

sdas [7]

Explanation:

A change that does not cause any change in chemical composition of a substance is known as a physical change.

For example, mass, density, volume etc are all physical changes.

On the other hand, a change that brings change in chemical composition of a substance is known as chemical change.

For example, combustion, toxicity, reactivity etc are all chemical changes.

Hence, following statements are identified as chemical or physical changes as follows.

(a) Oxygen gas supports combustion : Chemical change

(b) Fertilizers help to increase agricultural production : Chemical change

(c) Water boils below $100^{o}C$ on top of a mountain : Physical change

(d) Lead is denser than aluminum : Physical change

(e) Uranium is a radioactive element : Chemical change

7 0

3 years ago

Which describes the normal boiling point of a substance?

kicyunya [14]

Answer:

I think it's D

Explanation:

I'm so sorry if that's wrong, hope it helps!

6 0

3 years ago

What is the shortest wavelength in the Balmer series

MissTica

The largest energy release will take place when the electron jumps between the greatest number of levels. In this case from infinity down to 2

This is the emitted photon with the most energy ( in the Balmer series), the highest frequency and therefore the shortest wavelength.

Balmer's original formula was

Wavelength = 3645.6 . 10^–10 ( n^2 / (n^2 – 4) )

When n => infinity

Wavelength = 3.6456 . 10^–7 m ( or 364.5 nm)

7 0

3 years ago

Read 2 more answers

(a) Find the concentration of electrons and holes in a sample of germanium that has a concentration of donor atoms equal to 1015

matrenka [14]

Answer:

a) Germanium = 5.76 x 〖10〗^11 〖cm〗^(-3) , Semiconductor is n-type.

b) Silicon = 2.25 x 〖10〗^5 〖cm〗^(-3) , Semiconductor is n-type.

For clear view of the answers: Please refer to calculation 5 in the attachments section.

Explanation:

So, in order to find out the concentration of holes and electrons in a sample of germanium and silicon which have the concentration of donor atoms equals to 〖10〗^15 〖cm〗^(-3). We first need to find out the intrinsic carrier concentration of silicon and germanium at room temperature (T= 300K).

Here is the formula to calculate intrinsic carrier concentration: For calculation please refer to calculation 1:

So, till now we have calculated the intrinsic carrier concentration for germanium and silicon. Now, in this question we have been given donor concentration (N_d) (N subscript d), but if donor concentration is much greater than the intrinsic concentration then we can write: Please refer to calculation 2.

So, now we have got the concentration of electrons in both germanium and silicon. Now, we have to find out the concentration of holes in germanium and silicon (p_o). (p subscript o)

Equation to find out hole concentration: Please refer to calculation 3. and Calculation 4. in the attachment section.

Good Luck Everyone! Hope you will understand.

6 0

3 years ago