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2 years ago

15

Based on your observations and your understanding about how heat moves (from hot to cold), write a hypothesis that describes whi

ch material (aluminum foil OR bubble wrap) will best insulate ice and slow the transfer of heat.

1 answer:

Oksi-84 [34.3K]2 years ago

3 0

Answer:

wrapping a boiled water keeps the water hot..cus it's wrapped and no air can go out

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How might temperature changes in the human body have an impact on human health ?

MrRissso [65]

It can cause heat strokes anxiety<span />

7 0

3 years ago

What is the pH of a solution of RbOH with a concentration of 0.86 M? Answer to 2 decimal places

lubasha [3.4K]

Answer:The pH of the solution is given by pH=−log([H3O+])

Explanation:so you can't use

pH

=

−

log

(

0.150

)

because that's the concentration of the hydroxide anions,

OH

−

, not of the hydronium cations,

H

3

O

+

. In essence, you calculated the

pOH

of the solution, not its

pH

.

Sodium hydroxide is a strong base, which means that it dissociates completely in aqueous solution to produce hydroxide anions in a

1

:

1

mole ratio.

NaOH

(

a

q

)

→

Na

+

(

a

q

)

+

OH

−

(

a

q

)

So your solution has

[

OH

−

]

=

[

NaOH

]

=

0.150 M

Now, the

pOH

of the solution can be calculated by using

pOH

=

−

log

(

[

OH

−

]

)

−−−−−−−−−−−−−−−−−−−−

In your case, you have

pOH

=

−

log

(

0.150

)

=

0.824

Now, an aqueous solution at

25

∘

C

has

pH + pOH

=

14

−−−−−−−−−−−−−−so you can't use

pH

=

−

log

(

0.150

)

because that's the concentration of the hydroxide anions,

OH

−

, not of the hydronium cations,

H

3

O

+

. In essence, you calculated the

pOH

of the solution, not its

pH

.

Sodium hydroxide is a strong base, which means that it dissociates completely in aqueous solution to produce hydroxide anions in a

1

:

1

mole ratio.

NaOH

(

a

q

)

→

Na

+

(

a

q

)

+

OH

−

(

a

q

)

So your solution has

[

OH

−

]

=

[

NaOH

]

=

0.150 M

Now, the

pOH

of the solution can be calculated by using

pOH

=

−

log

(

[

OH

−

]

)

−−−−−−−−−−−−−−−−−−−−

In your case, you have

pOH

=

−

log

(

0.150

)

=

0.824

Now, an aqueous solution at

25

∘

C

has

pH + pOH

=

14

−−−−−−−−−−−−−−

3 0

2 years ago

Helpppppppppppppp please

Mama L [17]

1)
-Lithium: Lithium got 3 protons, so it atomic number is 3. It is located on the first column of the periodic table, and belonging to the alkali metal. So lithium is a metal. Lithium is highly reactive.
-Neon: It is located on the 18th column of the periodic table, and belong to the noble gases. So Neon is a nonmetal. Neon's reactivity is very low.
-Fluorine: Located on the 17th column of the periodic metal, fluorine is a nonmetal, and belong to the halogen family. Fluorine's reactivity is high.

2)
-Vertical columns of the periodic table are called columns. There is 18 column in the periodic table, and each one represent a chemical family.
-Horizontal rows of the periodic table care called periods. There is 7 periods in the periodic table.
-The number of protons in an atom is that element's atomic number. And since the atom is electrically neutral, the number of protons is equal to the number of electrons. So if you have the number of electrons, you can still find the atomic number.
-The total of protons and neutrons in an atom is that element's atomic mass. Based on the formula A = Z + N, where A represents the atomic mass, Z the atomic number (number of protons) and N the number of neutrons.
-The elements in group 1 are the most reactive metals. This group is called the Alkali metals. They only have 1 electron in their outer shell which makes them always ready to lose an electron in an ionic bonding.
-The elements in group 17 are the most reactive nonmetals. This group is called the Halogens, with 7 electrons in their outer shell which makes them always ready to win an electron in an ionic bonding.
-The elements in group 18 are the most unreactive elements. This group is called the Noble gases. Their outer shell is always full, so it can't do reactions.

Hope this Helps! :)

4 0

3 years ago

Amount moles 167 g of nitrogen

skad [1K]

11.9 if i read your question correctly sorry if it’s wrong lol

5 0

3 years ago

Mixture of 120 grams of KClO3 and 300 grams of water until all of the KClO3 has dissolved. At what temperature does this occur?

lozanna [386]

240°C is required to dissolve 120 grams of KClO₃ in 300 g of water.

Explanation:

As per the solubility curve graph of different salts dissolved in 100 g of water, it can be noted that the KClO₃ gets saturated at 100 °C with the solubility of 59 g in it. But here the water is taken as 300 g and the salt is taken as 120 g. The graph shows the solubility of grams of salt in 100 g of water.

So, then we have to find what is the gram of salt present in 100 g of water for the present sample.

300 g of water contains 120 grams of salt.

Then, 1 g of water will contain $\frac{120}{300}$ g of salt.

Then, 100 g of water will contain $\frac{120}{300}*100$ of salt. This means, 100 g of water will contain 40 g of salt in it.

Then, if we check the graph, the corresponding x-axis point on the curve for the y-axis value of 40 g will give us the temperature required to dissolve the salt in water. So 80°C will be required to dissolve 40 g of salt in 100 g of water.

Then, in order to get the temperature required to dissolve 120 g in 300 g of water, multiply the temperature by 3, which will give the result as 80×3=240 °C.

So, 240°C is required to dissolve 120 grams of KClO₃ in 300 g of water.

8 0

3 years ago