1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
postnew [5]
3 years ago
9

A travel mug of 91∘C coffee is left on the roof of a parked car on a cold winter day. The temperature of the coffee after t minu

tes is given by H=91(2)−t/14. After how many minutes will the coffee be only lukewarm (30∘C)?
Chemistry
1 answer:
GREYUIT [131]3 years ago
3 0

Answer: A

Explanation:

You might be interested in
What is the formula of the compounds Cl- and Na+
Whitepunk [10]
Na and Cl together form the compound
NaCl2

5 0
3 years ago
The electron cloud model describes which of the following?
HACTEHA [7]
1) The trails left by an electron as it moves around the nucleus
The electron model dictates that the electrons have no fixed position so it traces their path.
2) 8
Atomic number is equivalent to proton number
3) Its mass is lowered, but it is still the same element.
The element's identity is due to the number of protons; however, neutrons play a large role in an atom's mass. Thus, the mass will decrease but the element will be the same. Such variants are called isotopes.
8 0
3 years ago
What is the wavelength of radiation emitted when an electron goes from the n = 7 to the n = 4 level of the Bohr hydrogen atom? G
Phantasy [73]

Answer:

the wavelength of radiation emitted  is \mathbf{\lambda= 2169.62 \ nm}

Explanation:

The energy of the Bohr's hydrogen atom can be expressed with the formula:

\mathtt{E_n =- \dfrac{13.6\ ev}{n^2}}

For n = 7:

\mathtt{E_7 =- \dfrac{13.6\ ev}{7^2}}

\mathtt{E_7 =-0.27755 \ eV}

For n = 4

\mathtt{E_4=- \dfrac{13.6\ ev}{4^2}}

\mathtt{E_4 =- 0.85\ eV}

The  electron goes from the n = 7 to the n = 4, then :

\mathtt{E_7-E_4 = (-0.27755 - (-0.85) ) \ eV}

\mathtt{= 0.57245\ eV}

Wavelength of the radiation emitted:

\mathtt{\lambda= \dfrac{hc}{0.57245 \ eV}}

where;

hc  = 1242 eV.nm

\mathtt{\lambda= \dfrac{1242 \ eV.nm }{0.57245 \ eV}}

\mathbf{\lambda= 2169.62 \ nm}

4 0
3 years ago
Which of these is a compound?<br> A. Na<br> B. Cl<br> C. NaCl<br> D. C
shtirl [24]

Answer:

Option : C

Explanation:

Hope it helps you!

7 0
3 years ago
Read 2 more answers
What is the combining ratio of potassium with bromine?
shtirl [24]
1:1 They would have one of each per molecule
3 0
3 years ago
Read 2 more answers
Other questions:
  • What man-made carbohydrate is banned in Canada, China, and the European Union, but is legal in the United States?
    14·1 answer
  • Which description of nitrogen-15 is correct?
    11·1 answer
  • Which elements are more likely to lose electrons?<br> Ca, Li, F and Ne
    14·1 answer
  • Use the Henderson-Hasselbalch equation and your knowledge of ionization to help you answer this question. Aspirin is a weak acid
    8·1 answer
  • Which is a cationic detergent having four organic groups attached to a nitrogen atom and used to sanitize utensils? Select one:
    9·1 answer
  • CHEMISTRY HELP! Lewis structure rules<br><br> Please help, is this correct?
    7·1 answer
  • In which or areas on the image dose salinity of the ocean increases
    5·1 answer
  • Determine the compound type for the following formulas: C12H22011 Mg(OH)2 H20 Cu3Zn2 Au <br>​
    11·2 answers
  • PLEASE HELP
    14·1 answer
  • A______Occouring________Solid that has a crystal structure and a definite______composition.
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!