Short Answer Questions 18 points

1) What year was Mendeleev born? _______________________________________
2) Where was Mendeleev born? ______________________________________
3) Explain how Mendeleev arranged his periodic table.______________________________________
4) What were the 3 Elements that were missing from Mendeleev’s Periodic Table?
__________________________________________________________________
5) When did Mendeleev die? Exact date ____________________________________
6)Which particles are in the nucleus of an atom? ______________________________

Answer:

Zero

Explanation:

An an equal mixture of the R and S enantiomers of carvone is called a racemic mixture.

In a racemic mixture, the R enantiomer rotates plane polarized light in one direction while the S enantiomer rotates plane polarized light in another direction.

This cancels out the rotation due to each enantiomer since they are equal in magnitude but opposite in direction leading to a specific rotation of zero for the racemic mixture.

Answer:

At 10ºC or 50ºF water can cotain the most dissolved sugar.

Answer:

What is the question?

Answer: The percent yield of the reaction is 77.0 %

Explanation:

[tex]2Pb+O_2\rightarrow 2PbO[/tex]

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

[tex]\text{Number of moles of lead}=\frac{451.4g}{207.2g/mol}=2.18moles[/tex]

[tex]\text{Number of moles of lead oxide}=\frac{374.7g}{223.2g/mol}=1.68moles[/tex]

According to stoichiometry:

2 moles of [tex]Pb[/tex] produces = 2 moles of [tex]PbO_2[/tex]

2.18 moles of [tex]Pb[/tex] is produced by=[tex]\frac{2}{2}\times 2.18=2.18moles[/tex] of [tex]PbO_2[/tex]

Mass of [tex]PbO_2[/tex] =[tex]moles\times {\text {Molar mass}}=2.18\times 223.2g/mol=486.6[/tex]

percent yield =[tex]\frac{374.7g}{486.6g}\times 100=77.0\%[/tex]

Answer:

Alkali Metals

Explanation:

They're the most reactive elements in group one.

Answer:

I hope you do well on the test good luck

Explanation:

Answer:

Kr, Ar, Ne, N

Explanation:

Hope this helps

Answer:

D. Electron pairs repelling each other push atoms apart

Explanation:

Hope this helps :) I just got it wrong on ap3x so I'm sure this is right

The VSEPR theory explain molecular shape by stating that the Electron pairs repelling each other push atoms apart. Hence, Option (D) is correct

Valence shell electron pair repulsion (VSEPR) theory, is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms.

It is also named the Gillespie-Nyholm theory after its two main developers, Ronald Gillespie and Ronald Nyholm.

Therefore, The VSEPR theory explain molecular shape by stating that the Electron pairs repelling each other push atoms apart. Hence, Option (D) is correct.

Learn more about VSEPR theory here ;

https://brainly.com/question/2293021

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Answer:

(3) sorry if I'm wrong

7.  (1-fertilization [sorry if wrong again]

8. (4-mitosis

Explanation:

I'm learning about this right now...Sorry if I'm wrong but I'm pretty sure they're right! Hope this helps tho! if I'm right maybe mark me brainliest?

Answer:

Explanation:

1. Cornstarch and water - decantation

2. Iron and sulfur

3. Rice grains and stones - sieving

4. Pebbles and soil - decantation

5. Muddy water - decantation

6. Ground pepper and water - decantation

7. Flour and coarsely ground corn - sieving

8. Needles in a box of beads - using a magnet

9. Sesame seeds in soy sauce -

10. Pebbles and iron nails - using a magnet

11. Fine sand from rocks - sieving

12. Sand from water - filtration

13. Gravel and sand - sieving

14. Salt and iron filings - sieving

15. Pins from assorted buttons - using a magnet

16. Coconut oil from coconut milk - filtration

17. Sand and pebbles - sieving

18. Pasta from water - sieving

19. Sand and thumb tacks - using a magnet

20. Salt solution - filtration

Answer:

one example of chemical weathering is when carbon dioxide mixes with water.

Explanation:

when dioxide mixes with water it creates carbonation.

Answer:

ecstasy

Explanation:

Answer:

Carbohydrates

Explanation:

Living things use carbohydrates as their main source of energy. The breakdown of sugars, such as glucose, supplies immediate energy for cell activities. Plants, some animals, and other organisms also use carbohydrates for structural purposes.

Answer:

B) . six electrons in the triple bond of diatomic nitrogen

Explanation:

The three line in this Lewis dot structure represents the six electrons in the triple bond of diatomic nitrogen.

Nitrogen is made up of 7 electrons with 5 valence ones.

 A lewis structure is made up of the symbol of the element surrounded by dot to represent the valence electrons.

  In this nitrogen molecule, both species share  6 electrons. This makes each nitrogen atom isoelectronic with neon.

A compressor, condenser, and a evaporator

Answer:

The velocity would be if m was meters +1200

Explanation:

im smart

Answer:

This question is incomplete

Explanation:

However, when the carboxylic acids and esters put together are obtained, the procedure below can be followed in drawing and naming them.

For carboxylic acid,

1) it should be noted that the functional group here is -COOH which is drawn as -C = OH

      |

     OH

2) The carbon of the functional group is included among the carbon to be counted when naming the structure. For example, the compound below is propanoic acid.

CH₃CH₂COOH - As you can see that there are 3 carbons linked chain there.

3) As can be seen in (2) above, the suffix "oic" is used to name carboxylic acids

4) The carbon chain here is saturated (meaning there is no double or triple bond within the carbon chain)

Example of a structure of carboxylic acid is

H₃C - CH₂ - CH₂ - C = OH

                              |

                             OH

The structure above is a butanoic acid

For ester

1)The functional group here is -COO- . which can be drawn as

- C = O

   |

  O -

(meaning one oxygen atom is double bonded to the carbon and the other oxygen atom is bonded to another carbon chain)

2) The alkyl group attached to the oxygen atom is first of all mentioned before the carbon chain attached from the left is mentioned. For example, CH₃CH₂CH₂COOCH₂CH₃ is ethyl butanoate

3) As seen from (2) above, the suffix "oate" is used to end the name of esters

4) As also seen from (2) above, the carbon of the functional group is also included while counting the carbon chain of the parent name (butanoate).

5) The carbon chains here are also saturated.

Example of this ester is

CH₃CH₂C = O

              |

             O - CH₂CH₃

The name of this compound is ethyl propanoate

Answer:

option is (b)

Explanation:

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Answer:

20.180042 amu

Explanation:

From the question given above, the following data were obtained:

Isotope A (20Ne)

Mass of A = 19.9924356 amu

Abundance (A%) = 90.48%

Isotope B (21Ne):

Mass of B = 20.9938428 amu

Abundance (B%) = 0.27%

Isotope C (22Ne):

Mass of C = 21.9913831 amu

Abundance (C%) = 9.25%

Average atomic mass of Neon =.?

The average atomic mass of Neon can be obtained as follow:

Average atomic mass = [(mass of A × A%)/100] + [(mass of B × B%)/100] + [(mass of C × C%)/100]

= [(19.9924356 × 90.48)/100] + [(20.9938428 × 0.27) /100] + [(21.9913831 × 9.25) /100]

= 18.0891557 + 0.05668338 + 2.03420294

= 20.180042 amu

Therefore, the average atomic mass of Neon is 20.180042 amu

Answer:

V = 43.95 L

Explanation:

Given data:

Mass of CH₄ decomposed = 15.63 g

Volume of H₂O produced at STP = ?

Solution:

Chemical equation:

CH₄ + 2O₂    →       2H₂O  + CO₂

Number of moles of CH₄:

Number of moles = mass/molar mass

Number of moles = 15.63 g/ 16 g/mol

Number of moles = 0.98 mol

Now we will compare the moles of H₂O with CH₄.

                         CH₄              :              H₂O

                           1                 :                2

                        0.98             :            2×0.98 = 1.96 mol

Volume of hydrogen:

PV = nRT

1 atm × V = 1.96 mol × 0.0821 atm.L/mol.K × 273.15 K

V = 43.95atm.L / 1atm

V = 43.95 L

Answer:

[tex]m_{CO2}=8.33gCO2[/tex]

Explanation:

Hello.

In this case, since the chemical reaction is:

[tex]C_7H_5N_3O_6(s)+\frac{21}{4} O2(g)\rightarrow 7CO_2(g)+\frac{3}{2} N_2(g)+\frac{5}{2} H_2O(l)[/tex]

Thus, since we have the initial moles of TNT:

[tex]n_{TNT}=25.7g*\frac{1mol}{227.13g} =0.113mol[/tex]

And the initial moles of oxygen given the ideal gas equation:

[tex]n_{O_2}=\frac{6.93atm*0.5L}{0.082\frac{atm*L}{mol*K}*298K}=0.142molO_2[/tex]

Given the 1:7 mole ratio between TNT and carbon dioxide and the 21/4:7 mole ratio between oxygen and carbon dioxide, we compute the yielded moles by each reactant:

[tex]n_{CO_2}^{by\ TNT}=0.113molTNT*\frac{7molCO_2}{1molTNT}=0.791molCO_2\\\\ n_{CO_2}^{by\ O_2}=0.142molO_2*\frac{7molCO_2}{21/4molO_2}=0.189molCO_2[/tex]

Thus, since oxygen yields less moles of carbon dioxide than TNT, we infer it is the limiting reactant, therefore, the produced mass of carbon dioxide is:

[tex]m_{CO2}=0.189molCO2*\frac{44.01gCO2}{1molCO2}\\\\m_{CO2}=8.33gCO2[/tex]

Best regards!

Answer:

During the reaction, chemical bonds break in the reactants and new chemical bonds form in the products.

Answer:

d. Atoms are rearranged.

Explanation:

Answer:

light bulb B

Explanation:

more resistance

Answer:

68.48%

Explanation:

The percent mass of an element in a compound tells us about the amount of such element contributed to the total compound.

In this case, 7.28 g sample of chromium metal was heated to produce chromium oxide with weight of 10.63 g. The percent mass of chromium in chromium oxide can be calculated by using the formula:

%mass of Cr = mass of Cr/mass of Chromium oxide × 100%

%mass of Cr = 7.28/10.63 × 100

%mass of Cr = 0.6848 × 100

%mass of Cr = 68.48%

Answer:

liquid

Explanation:

correct answer hope it helps

Answer:

The answer is "[tex]37.45364 \ g[/tex]"

Explanation:

Equation:

[tex]2AgNO_3 (aq) + Na_2CO_3 (aq) \longrightarrow Ag_2CO_3 (s) + 2NaNO_3 (aq)[/tex]

Calculating  the mol of  [tex]AgNO_3[/tex]:

[tex]\to V = 40.0 mL\\\\[/tex]

       [tex]= 40.0 \times 10^{-2} \ L \\\\[/tex]

[tex]\to n = Molarity \times Volume \\\\[/tex]

       [tex]= 0.679 \times 40.0 \times 10^{-2}\\\\= 27.16 \times 10^{-2} \ mol[/tex]

mol of [tex]Ag_2CO_3= \frac{1}{2} \times n\\\\[/tex]

                         [tex]= \frac{1}{2} \times 27.16 \times 10^{-2}\\\\= 13.58 \times 10^{-2}\\\\[/tex]

Calculating the molar mass of [tex]Ag_2CO_3[/tex],:

[tex]= 2\times MM(Ag) + 1 \times MM(C) + 3 \times MM(O)\\\\= 2 \times 107.9 + 1 \times 12.01 + 3 \times 16.0\\\\= 275.81 \ \frac{g}{mol}[/tex]

Calculating the mass of [tex]Ag_2CO_3[/tex],

[tex]m = mol \times molar \ mass[/tex]

   [tex]= 13.38 \times 10^{-2}\ mol \times 2.758 \times 10^2 \ \frac{g}{mol}\\\\= 37.45364 \ g[/tex]