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
Zepler [3.9K]
3 years ago
10

Some species are no longer living but we know they existed one time. we know this because....

Chemistry
1 answer:
Dahasolnce [82]3 years ago
6 0
We know this because of the discovery of fossils and bones. We can find out roughly when they existed because of carbon dating.
You might be interested in
Which element in period 3 has three times the electronegativity value compared to that of li in period 2
victus00 [196]

Answer:

Nitrogen

Explanation:

Elements in period two includes lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine and neon.

According to periodic trends, the electro negativity values are expected to increase across the period up to fluorine. Hence, as we go right wards, we encounter elements with higher electronegative values.

While lithium has an electronegative value of 1 , the electronegative value of element nitrogen is thrrr times this which is equal to three

7 0
3 years ago
Read 2 more answers
Is a blood vessel an organ
Alika [10]
Yes, but they are tubular organs and like all other organs are made up of tissues
7 0
3 years ago
Read 2 more answers
What is the molarity of 225 grams of Cu(NO2)2 in a total volume of 2.59 L?
Kay [80]

Answer:

The molarity is 0.56\frac{moles}{L}

Explanation:

In a mixture, the chemical present in the greatest amount is called a solvent, while the other components are called solutes. Then, the molarity or molar concentration is the number of moles of solute per liter of solution.

In other words, molarity is the number of moles of solute that are dissolved in a given volume.

The Molarity of a solution is determined by:

Molarity (M)=\frac{number of moles of solute}{Volume}

Molarity is expressed in units (\frac{moles}{liter}).

Then you must know the number of moles of Cu(NO₂)₂. For that it is necessary to know the molar mass. Being:

  • Cu: 63.54 g/mol
  • N: 14 g/mol
  • O: 16 g/mol

the molar mass of Cu(NO₂)₂ is:

Cu(NO₂)₂= 63.54 g/mol + 2*(14 g/mol + 2* 16 g/mol)= 155.54 g/mol

Now the following rule of three applies: if 155.54 g are in 1 mole of the compound, 225 g in how many moles are they?

moles=\frac{225 g*1 mole}{155.54 g}

moles= 1.45

So you know:

  • number of moles of solute= 1.45 moles
  • volume=2.59 L

Replacing in the definition of molarity:

Molarity=\frac{1.45 moles}{2.59 L}

Molarity= 0.56\frac{moles}{L}

<u><em>The molarity is 0.56</em></u>\frac{moles}{L}<u><em></em></u>

5 0
3 years ago
If you want to use a serial dilution to make a 1/50 dilution. The first dilution you make is a 1/5 dilution with a total volume
uranmaximum [27]

Answer:

0.2 mL stock solution, 0.8 solvent, 0.1 mL first solution and 0.9 solvent

Explanation:

The final volume for fist solution is 1 mL and concentration must will be 1/5, then 1 mL/5=0.2 mL. For complete the 1 mL add the missing solvent volume 1 mL-0.2 mL=0.8 mL. For second solution, assuming final volume is 1 mL, and concentration 1/10, then we have 1 mL /10=0.1 mL solution 1/5. Completing volume, 1 mL-0.1 mL= 0.9 mL solvent.

7 0
3 years ago
A specific combination of bonded atoms which always react in the same way is known as
grigory [225]
A specific combination of bonded atoms which always react in the same way, regardless of the particular carbon skeleton is known as the functional group. These are specific groups of atoms or bonds within organic molecules that accounts for the characteristic chemical reactions of those molecules.  Examples of functional groups are the Carbonyl group, alkyl Halides, aldehydes and ketones among others.
4 0
3 years ago
Other questions:
  • Which of the following solids is the best insulator?
    6·2 answers
  • How many grams of a stock solution that is 92.5 percent H2SO4 by mass would be needed to make 250 grams of a 35.0 percent by mas
    10·1 answer
  • Which would result in radioactive decay? Check all that apply.
    5·2 answers
  • Which of the following is true for compounds?
    10·1 answer
  • The mass of an electron is about 9.11 × 10 -9 kg., write this whole number​
    13·1 answer
  • Karl went to the doctor complaining of a sore throat. The doctor performed
    5·1 answer
  • What element is solid at room temperature shiny malleable and a good conductor of heat
    14·1 answer
  • Find the % composition for each element in Zinc Chlorate
    12·1 answer
  • Help!!!
    8·2 answers
  • 2. Name the type of reaction.
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!