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
ale4655 [162]
2 years ago
8

In a periodic table, dots around an elements symbol indicate the number of valence electrons in an atom ? True Or False

Chemistry
1 answer:
Liono4ka [1.6K]2 years ago
6 0
True,I think.(so don't really count on my answer sorry :D)
You might be interested in
You collect a sample of gases from an indoor pool area. The sample contains air and water vapor. The total pressure is 100.18 ki
Nikolay [14]

C. 96.82 kPa because to find the amount of pressure the air is causing you need to subtract the amount of pressure the water vapor is causing because the only two gasses making up the air in the pool area are air and water vapor.

8 0
3 years ago
Read 2 more answers
0.53g of acetanilide was subjected to kjeldahl determination and the ammonia produced was collected in 50cm3 of 0.50M of h2so4.o
Lady bird [3.3K]

Answer:

10.57% of N in acetanilide

Explanation:

All nitrogen in the sample is converted in NH₃ in the Kjeldahl determination. The NH₃ reacts with H₂SO₄ as follows:

2NH₃ + H₂SO₄ → 2NH₄⁺ + SO₄²⁻

The acid in excess in titrated with Na₂CO₃ as follows:

Na₂CO₃ + H₂SO₄ → Na₂SO₄ + H₂O + CO₂

To solve this question we must find the moles of sodium carbonate = Moles of H₂SO₄ in excess. The added moles - Moles in excess = Moles of sulfuric acid that reacts:

<em>Moles Na₂CO₃ anf Moles H₂SO₄ in excess:</em>

0.025L * (0.05mol / L) = 1.25x10⁻³ moles Na₂CO₃ / 0.01360L =

0.09191M * 0.250L = 0.0230 moles H₂SO₄ in excess.

<em>Moles H₂SO₄ added:</em>

0.050L * (0.50mol / L) = 0.0250 moles H₂SO₄ added

<em>Moles that react:</em>

0.0250 moles - 0.0230 moles = 0.0020 moles H₂SO₄

<em>Moles of NH₃ = Moles N:</em>

0.0020 moles H₂SO₄ * (2mol NH₃ / 1mol H₂SO₄) = 0.0040 moles NH₃ = Moles N

<em>mass N and mass percent:</em>

0.0040 moles N * (14g / mol) = 0.056gN / 0.53g * 100 =

<h3>10.57% of N in acetanilide</h3>
7 0
2 years ago
The metal which does react vigorously with halogens to form halides?
pshichka [43]

Answer:

RUBIDIUM

Explanation:

5 0
3 years ago
Of the five salts listed below, which has the highest concentration of its cation in water? assume that all salt solutions are s
Zigmanuir [339]
First of all, I need to know what these five salts are. Luckily, I found a similar problem from another website which is shown in the attached picture. The Ksp is the solubility product constant. It follows the formula:

Ksp = [cation concentration]ᵃ[anion concentration]ᵇ
where a and b are the subscripts of the metal and nonmetal, respectively. 

For the solutions ahead, let x be the concentration of the cation.

A.  The formula is PbCr₂O₄.
2.8×10⁻¹³ = [x][x]
Solving for x, x = 5.29×10⁻⁷ M

B. The formula is Co(OH)₂. 
 1.3×10⁻¹⁵ = [x][x]²
Solving for x, x = 1.09×10⁻⁵ M

C. The formula is CoS. 
 5×10⁻²² = [x][x]
Solving for x, x = 2.24×10⁻¹¹ M

D. The formula is Cr(OH)₃. 
 1.6×10⁻³⁰ = [x][x]³
Solving for x, x = 3.56×10⁻⁶ M

E. The formula is Ag₂S. 
 6×10⁻⁵¹ = [x]²[x]
Solving for x, x = 1.82×10⁻¹⁷ M

<em>Thus,the highest concentration is letter B, Cobalt (II) Hydroxide.</em>

5 0
2 years ago
Calculate the amount of heat required to raise the temperature of a 24 g sample of water from 9°C to 23°C.
borishaifa [10]

Answer:

1400KJ/mol⁻¹

Explanation:

Amount of heat required can be found by:

Q = m × c × ΔT

<em>Where m is the mass, c is the specific heat capacity (4.2KJ for water) and ΔT is the change in temperature.</em>

Q = 24 × 4.2 × (23 - 9)

= 24 × 4.2 × 14

=   1411.2KJ/mol⁻¹

= <u>1400KJ/mol⁻¹</u>  (to 2 significant figures)

7 0
3 years ago
Other questions:
  • Why does the skateboarder continue to move forward when he hits the trash?
    7·2 answers
  • Oxygen atomic mass number ??
    12·2 answers
  • An element consists of two isotopes. One with a mass of 79.95 amu and an abundance of 29.9%. The second isotope has a mass of 81
    8·1 answer
  • Why aren't alkali metals found in pure form?
    10·1 answer
  • If an ice cube melts at 0ºC but water also freezes at 0ºC, what is the difference between melting and freezing in terms of…….
    7·1 answer
  • You have 0.2231 grams of an unknown monovalent salt (MCl). You treat it with an excess of AgNO3 and precipitate all the chloride
    9·1 answer
  • I find that there are 500 atoms of U-235 and 1500 atoms of Pb-207. If we assume the mineral contained only parent and no daughte
    8·1 answer
  • A chemical process involves adding various agents to a vat and then waiting for the agents to react to make a final compound. Th
    6·1 answer
  • 15. Why do many substances dissolve easily in water?
    12·2 answers
  • If salt water has a density of 1.2 g/mL, which object listed below would SINK? *
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!