Help Zone

SkillfulGrasshopper3789

Hello,

I'm having trouble balancing chemical equations. Could you give me something, please?

Thank you so much!

SkillfulGrasshopper3789

Good evening,

I have a problem with the following question:

"In increasing order of concentration, order the following solutions:

Sol. A: 0.1 g / L of CaCO3 in water

Sol. B: 5% m / V solution of ethanol in water

Sol. C: solution of 3 mol of CO2 in 60 mol of air

Sol. D: solution of 560 ppm "

Thank you for your help

SkillfulGrasshopper3789

Hello!

I have an exercise in science which tells me that my concentration is 0.10 M. But what is the unit “M”?

Thanks already!

SkillfulGrasshopper3789

What is the difference between a mole and the Avogadro number?

SweetCrocodile1896

Can you help me with the following exercise:

“Name the different effects of forces:

We push on a concrete block
We pull on a rope
We twist a rag
We press on a wooden plank held by two blocks
We tear a piece of fabric “

SweetCrocodile1896

How do we distinguish between elastic deformation, plastic deformation and rupture?

HumbleArmadillo3023

Why is my answer (c) incorrect? Isn't there an accurate front view in an isometric projection?

Find the drawing

a)b)c) Neither; there is no front view in an isometric projection

Answer: a)

Ce contenu est protégé par le droit d'auteur. Toute reproduction à l'extérieur des forums Alloprof est interdite et pourra être considérée comme une violation du droit d'auteur.

Ce contenu est protégé par le droit d'auteur. Toute reproduction à l'extérieur des forums Alloprof est interdite et pourra être considérée comme une violation du droit d'auteur.

HumbleArmadillo3023

What are multiple view projections useful for? It seems to me that a frontal projection would do the job just as well?

HumbleArmadillo3023

What is the difference between the motion transfer and transformation mechanisms? I do not understand.

HumbleArmadillo3023

What is the difference between a motion transfer mechanism and a motion transformation mechanism? Can you give some examples? Thank you :)

HumbleArmadillo3023

How do you know which way a gear or wheel turns?

HumbleArmadillo3023

Hello.

I have just learned about transmission mechanisms and I am not sure I understand the difference between motor, driven, and intermediate transmission mechanisms.

Also, I do not understand how the direction of a rotation can change or not, and how some systems are reversible and others not.

Can you give me some examples? Thank you :)

HumbleArmadillo3023

How do I calculate the volume of solvent to add in a dilution? I am given an initial concentration (0.25 g / L), the volume (14 ml) and I want the final concentration (0.20 g / L).

Usually, I would use c1 * V1 = C2 * v2 to find the final volume, but I don't know which volume to add.

Can you help me?? Thank you

ShyMoon4957

How do we compare different solutions according to their concentration?

ShyMoon4957

Hello! I have a homework assignment on dilution and I have 3 questions

1) What is the difference between a dissolution and a dilution?

2) Does a dilution always lower the concentration?

3) My homework says that my final solution has a volume of 100ml and a concentration of 0.24g / ml, then the initial solution has a volume of 75ml. How do I find the initial concentration ??

Thanks in advance :)))

ShyMoon4957

Hello!

In my homework, it requires converting a 77 g / ml concentration into a mass volume percentage, but I don't know how.

Thanks for your help in advance!

ShyMoon4957

Good evening,

Can you show me how to solve a complete dilution problem? I have a lot of difficulty with that.

ShyMoon4957

Hello? I am lost here, is a colloid a heterogeneous or homogeneous mixture? Thank you

ShyMoon4957

Hello! Can you give me concrete examples of the different mixtures? (heterogeneous, homogeneous)

Thank you!

FastFox1311

Hello,

I can't quite understand the concept of solubility, could you please explain it to me?

Thanks a lot!

FastFox1311

Hello,

I can't quite understand the solutions and the difference between solute and solvent. Could you explain it to me, please?

Thanks a lot!

ShyMoon4957

Someone throws a huge 300 kg object into a 40,000 L swimming pool without any splashes being produced. The pool’s volume is measured afterwards, thus showing that it reaches 45,000 L. What is the density of the object? Help !?!

FastFox1311

Hello! Must I measure a solid with a ruler to determine its density ? I no longer remember :(

SweetCrocodile1896

Hi, how come oil floats on the water? Thank you for explaining this to me 🙂

SweetCrocodile1896

Hi!

What causes one substance to have a higher density than another? thank you

SweetCrocodile1896

Hello,

I have to find the density of a solid for my science lab, but don't know how to do it. Can you explain me how, please?

Thanks a lot!

SweetCrocodile1896

Hi! I have a lab this week on the density of gases, liquids, and solids.

I understand that for the liquids I can weigh and measure the volume, but I have two questions:

1) how do I measure the mass of a gas?

2) how do I measure the volume of a solid?

thanks in advance :))

SweetCrocodile1896

Are all the material properties advantageous? For example, why is fragility an advantage?

QuietDragon2728

Hello,

I can't seem to understand how energy can manifest naturally. Can you explain to me how it manifests please?

Thanks a lot!

QuietDragon2728

Hello,

I can't figure out what the motion transfer mechanisms are used for and what the mechanisms are. Can you help me please!

Thanks a lot!

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