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
Ivan
2 years ago
13

1. Who was the first person to create a periodic table? When?

Chemistry
2 answers:
Hatshy [7]2 years ago
8 0

Answer:

Mendeleev discovered the periodic table (or Periodic System, as he called it) while attempting to organise the elements in February of 1869.

Explanation:

goldenfox [79]2 years ago
7 0

Mendeleev discovered the periodic table (or Periodic System, as he called it) while attempting to  the elements in February of 1869. also I made a enderBender of our pfp!

You might be interested in
Use the bond energies to answer the question.
Schach [20]

Answer:

D

Explanation:

Hello!

This is a topic I just learned this year so I might not help the best as of explaining. But I will try my best.

To solve this problem, we must first figure the balanced equation.

H₂+O₂=H₂O₂

Now, we have to find the bond energy of the reactants and products. This is how.

Let's find the reactant first.

For the compound H₂, the Lewis dot structure says that it only consists of one singular bond. So the bond energy of H₂ would be 432.

For the compound O₂, the Lewis dot structure that is the best out of the resonance structures form a double bond. Let's use the bond energy 495 for this since there are double bonds and we need the corresponding double bond energy to make the bond energy accurate.

Let's add this amount together. 927

Now, we have to find the bond energy of the products.

H₂O₂ sounds complicated but it's fairly easy. When you write the Lewis dot structure for this specific compound, you will get something along the lines of this:

H-O-O-H (disregarding lone pairs)

In this compound, there are two bonds of H-O and one bond that is a O-O. This might take you a long time to see this, but just think of what atom is touching the atom next door. This might help distinguish the bonds there are between the compound.

Let's take the bond energy of H-O (467) and multiply this by two since we have two. Add that number to the bond energy of O-O (146). We should have the numbers 1080.

Since the problem is asking for the difference in total energy between the reactants and products, let's subtract the total bond energy of the products-reactants.

1080-927=153

Therefore, your final answer of the total bond energy is 153.

4 0
2 years ago
A 5.00 gram sample of magnesium sulfate hydrate (epsom salt) is heated in the lab to form anhydrous magnesium sulfate. After hea
Ostrovityanka [42]

Answer:

The answer to your question is  MgSO₄ 5H₂O

Explanation:

Data

mass of MgSO₄ = 2.86 g

mass of H₂O = 2.14 g (5 - 2.86)

Process

1.- Calculate the molecular mass of the compounds

MgSO₄ = 24 + 32 + (16 x 4) = 120

H₂O = 16 + 2 = 18

2.- Convert the grams obtain to moles

                        120 g of MgSO₄  --------------- 1 mol

                         2.8 g                  ----------------  x

                         x = (2.8 x 1)/120

                        x = 0.024 moles

                         18 g of H₂O --------------------- 1 mol

                         2.14 g           -------------------- x

                         x = (2.14 x 1)/18

                         x = 0.119

3.- Divide by the lowest number of moles

MgSO₄  = 0.024/0.024 = 1

H₂O = 0.119/ 0.024 = 5

4.- Write the molecular formula

                   MgSO₄5H₂O                        

5 0
3 years ago
(7th grade science question)
Akimi4 [234]
The most accurate way to measure a dry ingredient like flour, sugar or chocolate chips is in terms of its weight, which is measured in regular ounces.
7 0
3 years ago
At construction sites, workers often reduce erosion by ____.
Naddik [55]
<h3><u>Answer;</u></h3>

<em>All the above</em>

Workers at construction sites often reduce erosion by;

  • <em>Moving excess sediment back to its original location </em>
  • <em>Planting trees </em>
  • <em>Spraying water on bare soil</em>
<h3><u>Explanation;</u></h3>
  • Soil erosion is a naturally occurring process which involves the wearing away of the topsoil by natural forces such as wind, water or other forces associated with farming.
  • <em><u>Construction of roads and buildings results to large amounts of soil erosion around the world. It is therefore important to put measures that would help reduce soil erosion at construction sites</u></em>. These measures uses principals of soil control such as implementing sediment control, limiting soil exposure, reducing the runoff velocity, and modifying topography among others.
5 0
3 years ago
What’s molar mass? For chemistry
Alik [6]
In chemistry, the molar mass of a chemical compound is defined as the mass of a sample of that compound divided by the amount of substance in that sample, measured in moles.
3 0
3 years ago
Other questions:
  • When a chemical reaction releases energy it is called what
    7·2 answers
  • Using the activity series provided. Which reactants will form products?
    15·2 answers
  • Why should copper and sodium be in different groups
    10·1 answer
  • What happens if a solid changes the state of substance to liquid?
    14·2 answers
  • The concentration of hydroxide ions is greater than the concentration of hydronium ions for acidic solution. True or false.
    6·1 answer
  • Which volcanoes are located on a diverging boundaries
    12·1 answer
  • 5. What is metallic bonding?<br> 6. Why are metals shiny?
    14·1 answer
  • Compare the viscosity property of solid and liquid. ​
    11·1 answer
  • Please help it’s due by midnight I’ll mark you brainiest if you’re able to help
    14·1 answer
  • Which describes a property of water that allows plants to transfer it from their roots to their leaves? Water exhibits weak adhe
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!