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
kkurt [141]
3 years ago
6

50 points!!! Please help me

Chemistry
1 answer:
oee [108]3 years ago
5 0
30. mixture of compounds
31. compound
32. element
33. compound
34. compound
34. mixture of elements and compounds
You might be interested in
How many moles of oxygen are in 25.45 g of caco3?
emmainna [20.7K]
From the periodic table:
mass of oxygen = 16 grams
mass of calcium = 40 grams
mass of carbon = 12 grams
mass of CaCO3 = 40 + 12 + 3(16) = 100 grams
Therefore, each 100 grams of CaCO3 contains 3 moles of oxygen
To know the number of oxygen moles in 25.45 grams, we will simply do cross multiplication as follows:
number of oxygen moles = (25.45 x 3) / 100 = 0.7636
3 0
3 years ago
The degree to which a weak base dissociates is given by the base-ionization constant, Kb. For the generic weak base, B B(aq)+H2O
Colt1911 [192]

Answer:

pH of a 0,245 M ammonia solution is 11,3 and percent ionization is 0,86%

Explanation:

For the equilibrium buffer of NH₃:

NH₃ + H₂O ⇄ NH₄⁺ + OH⁻; kb = 1,8x10⁻⁵

kb = [NH₄⁺] [OH⁻] / [NH₃] <em>(1)</em>

When 0,245 M of NH₃ is added, the equilibrium concentrations are:

[NH₃] = 0,245 - x

[NH₄⁺] = x

[OH⁻] = x.

Replacing this values in (1)

1,8x10^{-5} = \frac{x^2}{0,245 - x}

x² + 1,8x10⁻⁵x - 4,41x10⁻⁶ = 0

Solving for x:

x = -0,00211 No physical sense. There are not negative concentrations.

x = 0,00211 Real answer

Thus [OH⁻] in equilibrium is 0,00211 M.

As pOH = -log [OH⁻] and 14 = pH + pOH

pH of 0,00211 M is <em>11,3</em>

It is possible to calculate the percent ionization thus:

Percent ionization = [OH−] equilibrium / [B] initial×100%

Replacing:

0,00211 / 0,245 × 100 = <em>0,86%</em>

I hope it helps!

6 0
3 years ago
What are some ways you can determine a chemical change has occured
FromTheMoon [43]

1. Color changes.

The Statue of Liberty, though known for its green color, was originally covered in a layer of copper. After a redox (reduction-oxidation reaction) the color changed due to a chemical change.

2. Gas Production

3. Light Produced

Light sticks work as the result of a chemical reaction between hydrogen peroxide and phenol oxalate ester.

4. Temperature Changes

5. Volume Change

4 0
2 years ago
Difference between clinical and laboratory thermometer
Setler79 [48]

Answer:

1)clinical thermometer has temperature range 35 to 42degree celcius where labouratery thermometer has -10 to 110 degree celcius.

2)clinical thermometer is used to measure body temperature whare labouratory thermometer is not used to measure body temperature

7 0
3 years ago
Read 2 more answers
Please Help Just one question! 15points and a brainliest (:
Wewaii [24]

Answer:

convolutions.

Explanation:

the hippocampus- complex structure with a major role in learning and memory

the hypothalamus - structure of the brain near the pituitary gland

brain stem - yet another structure

8 0
3 years ago
Read 2 more answers
Other questions:
  • When 28 g of nitrogen and 6 g of hydrogen react, 34 g of ammonia are produced. if 100 g of nitrogen react with 6 g of hydrogen,
    7·2 answers
  • Select the correct answer from each drop-down menu. How are real gases different from ideal gases? Real gases differ from ideal
    12·2 answers
  • An unbalanced chemical equation for the reaction of boron fluoride with lithium sulfite is shown below.
    12·1 answer
  • A fluorine ion has nine protons and a charge of -1. how many electrons are in an ion the fluorine. A. 1 B. 9 C. 10 D. 8
    7·2 answers
  • A pool is 59.8 m long and 26.6 m wide. If the average depth of water is 3.70 ft, what is the mass (in kg) of water in the pool?
    8·1 answer
  • Which is most likely to happen during a precipitation reaction?
    12·1 answer
  • Strontium-90, a radioactive isotope with applications in medicine, has a half-life of approximately 30 years. Out of a 100-gram
    7·1 answer
  • Calculate the density of carbon dioxide at STP
    15·1 answer
  • Which statement describes how the angle of insolation affects different areas of Earth?
    14·2 answers
  • Which of the following is a salt? <br> C6H12O6<br><br> O2<br><br> C2H2<br> K C l
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!