True or False. For solidification, a substance must absorb heat

HELP! HELP!<br> an element with 5 protons, and 8 electrons has an atomic number of?

LenKa [72]

Answer:

Explanation: 15

3 0

3 years ago

An atom is made of 16 protons, 17 neutrons, and 18 electrons. What is the mass number of

Nataliya [291]

Answer:

The answer is 33 .

Explanation:

The mass number of an atom is the atomic mass which consists of proton and neutron. This atom has 16 protons and 17 neutrons so it has a mass of 33 :

proton number + neutron number = nucleon number / atomic mass

16 + 17 = 33

6 0

2 years ago

What is the total number of sublevels in the fourth principal energy level

Yuki888 [10]

The answer is 4. It can hold 4 sublevels as s.p,d,f and it holds 32 electrons

8 0

3 years ago

What is the reason behind that the melting and boiling point of iron is more than that of sodium? Write any two differences betw

liraira [26]

Answer:

difference between metal and alloy is that the metal is a pure substance whereas the alloy is a mixture of two or more components.

Explanation:

Mostly the metalloids have the appearance just like the metallic appearance And also they are the brittle one's . Boron and silicon are the example. Note; By combining with other metals metalloid can form the alloy

5 0

2 years ago

For the equilibrium

Mamont248 [21]

Answer:

Equilibrium concentrations of the gases are

$H_2S=0.596M$

$H_2=0.004 M$

$S_2=0.002 M$

Explanation:

We are given that for the equilibrium

$2H_2S\rightleftharpoons 2H_2(g)+S_2(g)$

$k_c=9.0\times 10^{-8}$

Temperature, $T=700^{\circ}C$

Initial concentration of

$H_2S=0.30M$

$H_2=0.30 M$

$S_2=0.150 M$

We have to find the equilibrium concentration of gases.

After certain time

2x number of moles of reactant reduced and form product

Concentration of

$H_2S=0.30+2x$

$H_2=0.30-2x$

$S_2=0.150-x$

At equilibrium

Equilibrium constant

$K_c=\frac{product}{Reactant}=\frac{[H_2]^2[S_2]}{[H_2S]^2}$

Substitute the values

$9\times 10^{-8}=\frac{(0.30-2x)^2(0.150-x)}{(0.30+2x)^2}$

By solving we get

$x\approx 0.148$

Now, equilibrium concentration of gases

$H_2S=0.30+2(0.148)=0.596M$

$H_2=0.30-2(0.148)=0.004 M$

$S_2=0.150-0.148=0.002 M$

3 0

2 years ago

True or False. For solidification, a substance must absorb heat​

True or False. For solidification, a substance must absorb heat