What is the order of taxonomy of living things?

Hydrofluoric acid is used to etch grooves in glass because it reacts with the silica (sio2(s)) in glass. the products of the rea

kvv77 [185]

Answer is: coefficient is one.
Chemical reaction: SiO₂ + 4HF → SiF₄ + 2H₂O.
Reaction is balanced when there are equal numbers of elements in both side of the chemical reaction.
HF - hydrofluoric acid, highly corrosive, dissolves many materials.
SiF₄ - silicon tetrafluoride.

6 0

3 years ago

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Magnesium metal (0.100 mol) and a volume of aqueous hydrochloric acid that contains 0.500 mol of HCl are combined and react to c

jok3333 [9.3K]

Answer:

2.24 L of hydrogen gas, measured at STP, are produced.

Explanation:

Given, Moles of magnesium metal, $Mg$ = 0.100 mol

Moles of hydrochloric acid, $HCl$ = 0.500 mol

According to the reaction shown below:-

$Mg_{(s)} + 2HCl_{(aq)}\rightarrow MgCl_2_{(aq)} + H_2_{(g)}$

1 mole of Mg reacts with 2 moles of $HCl$

0.100 mol of Mg reacts with 2*0.100 mol of $HCl$

Moles of $HCl$ must react = 0.200 mol

Available moles of $HCl$ = 0.500 moles

Limiting reagent is the one which is present in small amount. Thus, $Mg$ is limiting reagent.

The formation of the product is governed by the limiting reagent. So,

1 mole of $Mg$ on reaction forms 1 mole of $H_2$

0.100 mole of $Mg$ on reaction forms 0.100 mole of $H_2$

Mole of $H_2$ = 0.100 mol

At STP,

Pressure = 1 atm

Temperature = 273.15 K

Volume = ?

Using ideal gas equation as:

$PV=nRT$

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

1 atm × V L = 0.100 × 0.0821 L.atm/K.mol × 273.15 K

⇒V = 2.24 L

2.24 L of hydrogen gas, measured at STP, are produced.

4 0

3 years ago

Which of the following is NOT something that electromagnetic waves and mechanical waves have in common?

Svetlanka [38]

Answer:

D. In both, vibrations occur in a parallel direction to the direction of the wave.

Explanation:

It is not true that in both mechanical and electromagnetic waves, vibrations occur in parallel direction to the direction of the wave.

As with all waves, they are disturbances that transfers energy without moving the materials of the medium.

Electromagnetic waves have only one way of propagation which is a vibration in both parallel and longitudinal direction.
Mechanical waves can be propagated either in a parallel direction or longitudinal direction and not both.

6 0

3 years ago

What is the energy of electromagnetic radiation with wavelength of 568 nm?

anygoal [31]

Apr 15, 2020 · 1 answer
How to get unblocked. 1. See answer. Add answer. Log in to add comment. lunlun02015 is waiting for your help. Add your

6 0

3 years ago

In which of the following compounds does the carbonyl stretch in the IR spectrum occur at the lowest wavenumber?

klio [65]

Answer:

a. Cyclohexanone

Explanation:

The principle of IR technique is based on the vibration of the bonds by using the energy that is in this region of the electromagnetic spectrum. For each bond, there is a specific energy that generates a specific vibration. In this case, you want to study the vibration that is given in the carbonyl group C=O. Which is located around 1700 cm-1.

Now, we must remember that the lower the wavenumber we will have less energy. So, what we should look for in these molecules, is a carbonyl group in which less energy is needed to vibrate since we look for the molecule with a smaller wavenumber.

If we look at the structure of all the molecules we will find that in the last three we have heteroatoms (atoms different to carbon I hydrogen) on the right side of the carbonyl group. These atoms allow the production of resonance structures which makes the molecule more stable. If the molecule is more stable we will need more energy to make it vibrate and therefore greater wavenumbers.

The molecule that fulfills this condition is the cyclohexanone.

See figure 1

I hope it helps!

4 0

3 years ago