Answer:
Explanation:
Noble gases are the least reactive of all known elements. That's because with eight valence electrons, their outer energy levels are full. The only exception is helium, which has just two electrons.
choose the letter that best describes the behavior of a substance during a phase change:
/A/ neither absorbs or releases energy
/B/ always absorbs energy
/C/ always releases energy
/D/ either absorbs or releases energy
Answer:
/D/ either absorbs or releases energy
Explanation:
During a phase change energy is either absorbed or released.
A phase change is a reversible process which occurs when a substance changes is its state from one form to another.
Phase changes are used to delineate physical changes.
A phase diagram provides a graphic representation of the change. The diagram can be 2 dimensional or 3 dimensional.How many moles are in a sample of 2.39 x 10^23 atoms of sodium (Na)
Answer:
The answer is 0.4 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\ [/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{2.39 \times {10}^{23} }{6.02 \times {10}^{23} } \\ = 0.39700996...[/tex]
We have the final answer as
0.4 molesHope this helps you
Need help ASAP please
Answer:Melting can create steam, kind of like a nukeular plant exept no nukulear rods
Which of the following is the correct model of C7H16?
A.
B.
C.
D.
Answer:
D
Explanation:
Option D gives the correct model of C7H16. From the option, one will discover that the model has 7 carbons in the backbone. If you count the attached hydrogen, you will discover that the hydrogen is 16 in total.
This model or skeletal structure of this element represents heptane. Heptane or n-heptane is known to be a straight-chain compound and an alkane. It's chemical formula can also be written as: H₃C(CH₂)₅CH₃ or C₇H₁₆.
This compound is known to be one of the main components of gasoline. It is known to be a volatile organic compound and a clear and colorless liquids with a petroleum-like odor.
Answer: D
Explanation: Just took the test
Does the use of lithium cause human health problems?
Answer:
Yes
Explanation:
Lithium can cause nausea, diarrhea, dizziness, change in heart rhythm, muscle weakness, fatigue, and a dazed feeling
Continued use of Lithium could mean fine tremor, frequent urination, and thirst
Source: Webmd.com
Which types of matter are made of atoms
a. Mixtures
b. Elements
C. Compounds
D. All of the above
Answer:
D all above yes I think it's all above
Answer: D
Explanation: All of the above.
Plz mark brainliest:)
25 cm of liquid 'A' and 20 cm of liquid
'B' are mixed at 25°C and the volume of
solution was measured to be 44.8 cm3
then correct reaction is
(A) A Hmix = 0, solution shows
ideal
Answer:
The correct option is;
(B) [tex]\Delta H_{mix} < 0[/tex], solution shows negative deviation
Explanation:
The given parameters are;
The available volume of liquid A = 25 cm³
The available volume of liquid B = 20 cm³
The volume of the solution (mixture) = 44.8 cm³
Therefore, we have;
[tex]\Delta _{mix} V < 0[/tex]
Which is one of the prerequisite for the formation of negative deviation
When a non-ideal solution shows negative deviation according to Raoult's Law, we have;
[tex]\Delta _{mix} H < 0[/tex], we have more heat released due to new molecular interactions.