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Likurg_2 [28]
3 years ago
15

Why are there only two elements in the first row of the periodic table?

Chemistry
1 answer:
Wittaler [7]3 years ago
7 0
Look in the internet
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A lead–tin alloy of composition 30 wt% Sn–70 wt% Pb is slowly heated from a temperature of 150°C (300°F).(a) At what temperature
Novay_Z [31]

Answer:

a) 231.9 °C

b) 100% Sn

c) 327.5 °C

d) 100% Pb

Explanation:

This is a mixture of two solids with different fusion point:

Tf_{Pb}=327.5 C

Tf_{Sn}=231.9 C

<u>Given that Sn has a lower fusion temperature it will start to melt first at that temperature. </u>

So the first liquid phase forms at 231.9 °C and because Pb starts melting at a higher temperature, that phase's composition will be 100% Sn.

The mixture will be completely melted when you are a the higher melting temperature of all components (in this case Pb), so it will all in liquid phase at 327.5 °C.

At that temperature all Sn was already in liquid state and, therefore, the last solid's composition will be 100% Pb.

3 0
3 years ago
Which of the following will increase the number of collisions without changing the energy of reactant molecules?
natulia [17]

Answer:increasing the concentration of reactants

Explanation:

Collision is the phenomenon in which the reactant molecules come to nearest closness,as a result the reactants are converted into products.

Now the number of effective collision is directly proportional to the number of reactants added..

6 0
3 years ago
I’d appreciate the help! :)
seraphim [82]

Answer: 300g

Explanation:

first we write the given values on top

224L. x

3 NO2 (g) + H2O (l) = 2HNO3 (l) + NO (g)

22.4L 30g

then we form a formula

224L/22.4L= x/30g

224*30/22.4

6720/22.4= 300g

7 0
3 years ago
If I want to lower the volume (loudness) I can do which of the following. Select all that apply.
nirvana33 [79]

Sound travels in waves and the height of the wave is the loudness of the sound.

To decrease sound, you need to make the waves not so high, so you can

- decrease the amplitude

- decrease the height of the crest   (lower the top of the wave down)

- increase the height of the trough  (bring the bottom of the wave up)

It's all about getting the wave to be closer to the center, to not be so high and low, but to be flatter.

(picture taken from sound . eduation website)

6 0
3 years ago
Chemical bonds are likely to form when_____
Viefleur [7K]

Answer: When the electrons in an element are more than the required, a bond is formed with other element which has deficiency of electron and in case when electrons are less in numbers the vice versa happens. Such kind of chemical bonds are known as ionic bond.

Explanation:

7 0
3 years ago
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