The whistle of a teakettle has a greater frequency than a drumbeat. True or false and why

What type of reaction is shown below? Check all that apply. Ca + 2H2O → Ca(OH)2 + H2 synthesis decomposition combustion single r

Ksju [112]

The balanced reaction is

Ca + 2H2O → Ca(OH)2 + H2

Here this reaction can be compared with

A + BC ---> AB + C

So here one reactant (A) is accepting a group which is being given by another compound (BC) however the A is not giving any group / element or ion

So this single displacement

Similarly in the given reaction

the anion OH- is only being replaced

The element Ca accepts OH- and H2O loses the same group to form new element H2

So the correct answer is

Single replacement also known as single displacement

3 0

3 years ago

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Under standard-state conditions, which of the following species is the best reducing agent? a. Ag+ b. Pb c. H2 d. Ag e. Mg2+

eimsori [14]

Answer: The correct answer is Option b.

Explanation:

Reducing agents are defined as the agents which help the other substance to get reduced and itself gets oxidized. They undergo oxidation reaction.

$X\rightarrow X^{n+}+ne^-$

For determination of reducing agents, we will look at the oxidation potentials of the substance. Oxidation potentials can be determined by reversing the standard reduction potentials.

For the given options:

Option a: $Ag^+$

This ion cannot be further oxidized because +1 is the most stable oxidation state of silver.

Option b: $Pb$

This metal can easily get oxidized to $Pb^{2+}$ ion and the standard oxidation potential for this is 0.13 V

$Pb\rightarrow Pb^{2+}+2e^-;E^o_{(Pb/Pb^{2+})}=+0.13V$

Option c: $H_2$

This metal can easily get oxidized to $H^{+}$ ion and the standard oxidation potential for this is 0.0 V

$H_2\rightarrow 2H^++2e^-;E^o_{(H_2/H^{+})}=0.0V$

Option d: $Ag$

This metal can easily get oxidized to $Ag^{+}$ ion and the standard oxidation potential for this is -0.80 V

$Ag\rightarrow Ag^{+}+e^-;E^o_{(Ag/Ag^{+})}=-0.80V$

Option e: $Mg^{2+}$

This ion cannot be further oxidized because +2 is the most stable oxidation state of magnesium.

By looking at the standard oxidation potential of the substances, the substance having highest positive $E^o$ potential will always get oxidized and will undergo oxidation reaction. Thus, considered as strong reducing agent.

From the above values, the correct answer is Option b.

8 0

3 years ago

Could volume by displacement be used to determine the volume of a lump of rock salt? Explain would be nice

Readme [11.4K]

Yes it could, but you'd have to set up the process very carefully.
I see two major challenges right away:

1). Displacement of water would not be a wise method, since rock salt
is soluble (dissolves) in water. So as soon as you start lowering it into
your graduated cylinder full of water, its volume would immediately start
to decrease. If you lowered it slowly enough, you might even measure
a volume close to zero, and when you pulled the string back out of the
water, there might be nothing left on the end of it.

So you would have to choose some other fluid besides water ... one in
which rock salt doesn't dissolve. I don't know right now what that could
be. You'd have to shop around and find one.

2). Whatever fluid you did choose, it would also have to be less dense
than rock salt. If it's more dense, then the rock salt just floats in it, and
never goes all the way under. If that happens, then you have a tough
time measuring the total volume of the lump.

So the displacement method could perhaps be used, in principle, but
it would not be easy.

5 0

3 years ago

Why California and Nevada have so many faults?

gtnhenbr [62]

Answer:

They are due to past earthquakes

6 0

3 years ago

1 question you still have about the concept

allochka39001 [22]

Answer:

what concept?

Explanation:

5 0

3 years ago

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