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3 years ago

Which of the following is a reasonable ground-state electron configuration?

1 answer:

6 0

Following Aufbau rule and Hund principle, the order of filling of the orbitals is this:

$1s^22s^22p^63s^23p^64s^23d^{10}...$

So, the first, second, and fourth option are not correct.

The third option does meet the filling order.

Answer: $1s^22s^22p^63s^23p^64s^23d^1$

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Can i titrate a solution of unknown concentration with another solution of unknown concentration and still get a meaningful answ

olga2289 [7]

Answer:

No, I don't think so at least

Explanation:

In chemistry, you do calculations to find the concentration of a solution with another solution of KNOWN concentration. Without concentrations of either solution, were would you get values from? Where would you start? :3

6 0

3 years ago

What causes some materials to have magnetic fields?

enyata [817]

Magnetic fields in certain materials (most commonly metals) are created due to moving electrons within these materials, which create an electric current.The distribution of electrons in these metals is uneven, resulting in an irregular rotation and lots of movement that then creates two magnetic poles (a north and south pole). When these poles align and face the same direction, they create a magnetic field.

6 0

3 years ago

The proccess of melting is also called cooling???

lesya692 [45]

Becouse melting point and cooling point are two opposite things one is 100degrees nd other 0degrees

5 0

3 years ago

Hydrogen, a potential future fuel, can be produced from carbon (from coal) and steam by the following reaction: C(s)+2H2O(g)→2H2

madam [21]

The question is incomplete , complete question is:

Hydrogen, a potential future fuel, can be produced from carbon (from coal) and steam by the following reaction:

$C(s)+ 2 H_2O(g)\rightarrow 2H_2(g)+CO_2(g).\Delta H=?$

Note that the average bond energy for the breaking of a bond in CO2 is 799 kJ/mol. Use average bond energies to calculate ΔH of reaction for this reaction.

Answer:

The ΔH of the reaction is -626 kJ/mol.

Explanation:

$C(s)+ 2 H_2O(g)\rightarrow 2H_2(g)+CO_2(g).\Delta H=?$

We are given with:

$\Delta H_{H-O}=459 kJ/mol$

$\Delta H_{H-H}=432 kJ/mol$

$\Delta H_{C=O}=799 kJ/mol$

ΔH = (Energies required to break bonds on reactant side) - (Energies released on formation of bonds on product side)

$\Delta H=(4\times \Delta H_{O-H})-(2\times \Delta H_{H-H}+2\times\Delta H_{C=O})$

$=(4\times 459 kJ/mol)-(2\times 432 kJ/mol+2\times 799 kJ/mol$

$\Delta H=-626 kJ/mol$

The ΔH of the reaction is -626 kJ/mol.

5 0

4 years ago

describe a general rule for predicting the motion of an object that is being pushed or pulled by unbalanced forces?

7nadin3 [17]

7th grade activities

Force and Motion

(with Work)

2010-2011

Outline of Topics:

1. Describing Motion: Graphing, Speed and Velocity

2. Describing Motion: Changing Velocity

3. Forces, Their Sizes and Direction

4. Force and Mass

5. Its a grave matter: gravity and inertia

6. Weight and Mass

7. All work and no play: Work and Energy

Appendices

1: 7th Grade Vocabulary Related to Force and Motion

2: Motion Detector Directions

3: Day 1 Graphs with Focus Question at the End

4: Day 1 Data Collection Sheet

5: Day 2 Student Problem Sheet

6: Day 2 Second Set of Problems

7: Day 2 Graphs for is the Velocity Changing

8: Day 3 Student Tables with Questions

9: Day 4 Frame for Science Notebook

10: Day 5 Skateboard Prediction and Actual Sheets

11: Day 6 Data Table

12: Day 7 Student Handout

13: Day 7 Force Arrows

14: Day 8 Data Analysis

15: Uncovering Student Ideas in Physical Science probes

16: National Enquirer advertisements

17: Excerpt from Joy Hakim’s The Story of Science: Newton at the Center, pages 172-183

18: Directions for converting You Tube videos to another media file

First topic: Describing motion

A three-day exercise

Learning goals

Reviewed from 6th grade (day 1):

I can interpret a position versus time line graph to determine types of one-dimensional motion of an object.

I can draw a position versus time line graph given appropriate data.

I can represent changes in motion in a variety of ways, including words, motion arrows, graphs, and by acting out.

(Day 2) I can use the information in a position vs. time graph to determine the speed of an object.

New for 7th grade: I can define velocity.

(Day 3) I can distinguish between speed and velocity.

Topic Word Bank

Speed Motion Velocity Direction Position Graph Distance Vertical Time Horizontal Rate of change Representation Slope Negative Positive

Sequence of Experiences Day 1: Interpretation of a Position/Time Graph Pairs and whole group 10 minutes Day 1: Creation of a Position/Time Graph Lab groups and whole group 25 minutes Day 1: Making Sense of Multiple Representations Whole Group 10 minutes Day 2: Calculating Speed Pairs and whole group 23 minutes Day 2: Differentiating Speed and Velocity Pairs and whole group 18 minutes Day 2: Exit Slip Individually 5 minutes Day 3 Intro Whole class 3 minutes Day 3:Collecting Initial Data In pairs 12 minutes Day 3:Interpreting Data Parts 1 and 2 In pairs, then groups of 4 20 minutes Day 3: Student Challenge Day 3: Class Discussion Whole class 7 minutes Day 4: Intro Day 4:Interpreting Data Parts 3, 4 and 5 Whole class Day 4: Processing Information Individual and Paired Day 4: Class Discussion Whole Class Day 4: Exit Slip Individually 3 minutes

Day 1 Focus Question: What can be learned from different representations of motion?

Materials and Preparation:

For the class:

6 0

3 years ago