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
cestrela7 [59]
4 years ago
13

What is the first anmial

Chemistry
1 answer:
denpristay [2]4 years ago
8 0
The first animal was called the comb jelly
You might be interested in
Where are the electrons found in Bohr's atomic model?
Zepler [3.9K]

Answer:

The answer to your question is letter D.

Explanation:

Bohr tells us that the electrons which have a negative charge clicle the orbits in specific nucleus, so the right answer is letter D.

Letter C is not possible because the electrons are in orbits circling the nucleus where the protons are.

Letter B is not correct because electrons are distributed in orbits but the amount of electrons in one orbit is different to the other one.

8 0
3 years ago
Balance the following redox equations by the half-reaction method:
frozen [14]

Answer:

a)  Mn^2+ + 2OH- + H2O2 → MnO2 + 2H2O

b) 2Bi(OH)3 + 3SnO2^2-  → 2Bi + 3SnO3^2- + 3H2O

c) Cr2O7^2- + 3C2O4^2- + 14H+ → 2Cr^3+ +7H2O + 6CO2

d) 2ClO3- + 2Cl- + 4H+   → Cl2 + 2H2O +2ClO2

e) 5 BiO3^- + 14 H+ + 2Mn^2+  → 5Bi^3+ + 7H2O + 2MnO4^-

Explanation:

<em>(a) Mn2 + H2O2 → MnO2 + H2O (in basic solution)</em>

Step 1: The half reactions

Oxidation: Mn2+ + 4OH- → MnO2 + 2H2O + 2e-

Reduction: H2O2 + 2e- + 2H2O  →  2H2O + 2OH-

Step 2: Sum of both half reactions

Mn2+ + 4OH- + H2O2  → MnO2 + 2H2O  + 2OH-

Step 3: the netto reaction

Mn^2+ + 2OH- + H2O2 → MnO2 + 2H2O

<em>(b) Bi(OH)3 + SnO2^2-  → SnO3^2- + Bi (in basic solution)</em>

Step 1: The half reactions

Reduction:  Bi(OH)3 + 3e-  → Bi

Oxidation : Sno2^2-  → SnO3^2- +2e-

Step 2: Balance the half reactions

2* (Bi(OH)3 + 3e-  → Bi + 3OH-)

3* (Sno2^2- +2OH-  → SnO3^2- +2e- + H2O)

Step 3: The netto reaction

2Bi(OH)3 + 3SnO2^2-  → 2Bi + 3SnO3^2- + 3H2O

<em>(c) Cr2O7^2- + C2O4^2- → Cr^3+ + CO2 (in acidic solution)</em>

Step 1: The half reactions

Reduction: Cr2O7^2- + 6e-  → 2Cr+

Oxidation : C2O4^2- → 2CO2 + 2e-

Step 2: Balance the half reactions

Cr2O7^2- + 6e-  +14H+  → 2Cr+ +7H2O

3*(C2O4^2- → 2CO2 + 2e-)

Step 3: The netto reaction

Cr2O7^2- + 3C2O4^2- + 14H+ → 2Cr^3+ +7H2O + 6CO2

<em>(d) ClO3^- + Cl^− </em>→<em> Cl^2 + ClO^2 (in acidic solution)</em>

Step 1: The half reactions

Reduction: 2 ClO3^- + 10e- → Cl2

                      ClO3^- + e- → ClO2

 2 Cl- + 2ClO3^- +8e- →2Cl2

Oxidation: 2Cl- → Cl2 + 2e-

                   Cl- → ClO2 + 5e-

Cl- +ClO3^- → 2ClO2 + 4e-

Step 2: Balance the reactions

2Cl- + 2ClO3^- + 8e- + 12H+ → 2Cl2 + 6H2O

2* (Cl- + ClO3^- + H2O → 2ClO2 + 4e- + 2 H+)

Step 3: The netto reaction

2ClO3^- + 2Cl- + 4H+   → Cl2 + 2H2O +2ClO2

<em>(e) Mn^2 + BiO3^− </em>→<em> Bi^3 + MnO^4− (in acidic solution)</em>

Step 1: The half reactions

Reduction: BiO3^- + 2e- → Bi^3+

Oxidation : Mn^2+ → MnO4^- +5e-

Step 2: Balanced the reactions

5* ( BiO3^- + 2e- + 6H+ → Bi^3+ + 3H2O)

2* ( Mn^2+ + 4H2O →MnO4^- + 5e- + 8H+)

Step 3: The netto reaction

5 BiO3^- + 14 H+ + 2Mn^2+  → 5Bi^3+ + 7H2O + 2MnO4^-

6 0
4 years ago
What is the effect of adding more water to the following equilibrium reaction?
Serhud [2]

Answer:

Option B is correct More hydrogen carbonate is formed

Explanation:

Step 1: Data given

The Principle of Le Chatelier says 'If the concentration of one of the reaction partners changes, the balance will shift to counteract that concentration change.

Step 2: When adding more H2O

For the equation CO2 + H2O --> H2CO3

If the H2O concentration is increased, the system will attempt to undo that change in concentration by shifting the balance to the right, and so the H2CO3 concentration will increase.

Option B is correct More hydrogen carbonate is formed

7 0
3 years ago
Given the density of iron (Fe) is 7.87 g/cm3, determine the mass of iron (in grams) in a rectangle block with the dimensions of
guapka [62]

Answer:

m=14,105.71 g Fe

Explanation:

Hello,

In this case, the first step is to compute the volume of the block considering the length, height and width:

V=L \times W \times H =12.5 in\times 3.50 in \times 2.50 in =109.375 in^3

Then, we compute the volume in cubic centimetres:

V=109.375in^3\times \frac{16.3871 cm^3}{1in^3} =1792.34cm^3

Finally, as the density is given by:

\rho =\frac{m}{V}

We solve for the mass:

m=\rho \times V= 7.87\frac{g}{cm^3} \times 1792.34 cm^3\\\\m=14,105.71 g Fe

Best regards.

8 0
3 years ago
How to identify whether is it solid/liquid/gas/aqeous?​
MA_775_DIABLO [31]

Answer:

You have to know what the three sates of matter are

Explanation:

4 0
3 years ago
Other questions:
  • How much energy is released when 0.40 mol C6H6(g) completely reacts with oxygen? 2C6H6(g) + 15O2(g) 12CO2(g) + 6H2O(g) kJ
    12·1 answer
  • In a solution, the solvent is the substance in greater supply. True or False
    7·1 answer
  • In the electromagnetic spectrum, ________ frequencies, ________ wavenumbers, and ________ wavelengths are associated with high e
    8·1 answer
  • NEED HELP!!! chemistry moles and grams questions
    13·1 answer
  • A 6-column table with 2 rows. The first column labeled number of washers has entries 1, 2. The second column labeled initial vel
    10·2 answers
  • 1. Which of the following bones of the skeleton would be classified as part 1 point
    15·1 answer
  • What does the octet rule state that explains why atoms bond?
    14·2 answers
  • What was the test or tests that made you decide if you compound was an aldehyde or a ketone and why?
    5·1 answer
  • What are families 3-12 on the periodic table called
    12·2 answers
  • Please tell me if i did it right. did i put the right electric charge
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!