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
k0ka [10]
3 years ago
6

Is the following sentence true or false? Mendeleev used his periodic table to predict the properties of undiscovered elements.

Chemistry
2 answers:
Amanda [17]3 years ago
7 0
False, his periodic table was the first one, nobody knew about more elements in that time rather than the ones in the periodic table
Vinvika [58]3 years ago
7 0
True because at the time some scientists did not know the unknown elements.
You might be interested in
The hydrogen atom is the simplest of all atoms. True or False?
irina [24]

true, it has zero nuetrons which easily makes it more simple then the rest

7 0
4 years ago
Read 2 more answers
Predict what would happen if plants disappear?
Yakvenalex [24]

Answer:

All secondary consumers will die because they will lose their food source

7 0
3 years ago
A total of 2.00 mol of a compound is allowed to react with water in a foam coffee cup and the reaction produces 126 g of solutio
Karo-lina-s [1.5K]

Answer:

  • <u>0.976 kJ/mol</u>

Explanation:

A foam coffe cup is considered a perfectly insulated system: heat energy is not exchanged with the surroundings.

Under that assumption, the heat released by the chemical reaction is equal to the heat absorbed by the system.

1. Heat absorbed by the system:

Use the equation Heat = Q = m × C × ΔT, with:

  • m = 126 g (the amount of solution produced)
  • C = specific heat of pure water = 4.186 J/gºC
  • ΔT = increase of temperature = 24.70 ºC - 21.00ºC = 3.70ºC

Q = 126g × 4.186J/gºC × 3.70ºC = 1,951.5J

<em><u></u></em>

<em><u>2. Enthalpy of the reaction</u></em>

The enthalpy must be reported in kJ/mol.

Then, convert juoles to kilojoules, dividing by 1,000; and divide by 2.00 moles, which is the amount of compound that reacted:

  • ΔHrxn = 1,951.5J × (1kJ / 1,000J) × (1 / 2mol) ≈ 0.9758 kJ/mol

Round to <em>3 significant figures</em>: 0.976 kJ/mol

4 0
3 years ago
If 832J of energy is required to raise the temperature of a sample of aluminum from 20.0° C to 97.0° C, what mass is the sample
LiRa [457]
Data:
Q (Amount of heat) = 832 J
m (mass) = ?
c (Specific heat) = <span>0.90 J/(g × ° C)
T (final) = 97 ºC
To (initial) = 20 ºC
</span>ΔT = T - To → ΔT = 97 - 20 → ΔT = 77 ºC

Formula:
Q = m*c*ΔT

Solving:
Q = m*c*ΔT
832 = m*0.90*77
832 = 69.3m
69.3m = 832
m =  \frac{832}{69.3}
\boxed{\boxed{m \approx 12.00\:g}}\end{array}}\qquad\quad\checkmark
5 0
3 years ago
3. Suggest . how to do an experiment to find the solubility of salt​
slamgirl [31]
You can put salt in water and record how long that takes the water to dissolve. And then have just water in a cup and see how long it takes the water ti dissolve compared to the salt water.
8 0
3 years ago
Other questions:
  • Which is an important indigestible carbohydrate in the diet?
    12·2 answers
  • A 420-N force acts on a 400-N object, and the force is from the north. In which direction will the object move?
    12·2 answers
  • What profession is responsible for providing short term care for people being transorted to the hospital?
    11·1 answer
  • Describe the difference between atoms,molecules and compunds please help<br>​
    5·2 answers
  • In the laboratory, a volume of 100 mL of sulfuric acid (H2SO4) is recorded. How many g are there of the liquid if its density is
    14·1 answer
  • If your car gets 30.3 mi/gal, how many gallons of gasoline would you use if you drove 506.3 miles? 1 mile = 5280 ft (exactly) In
    8·2 answers
  • How is the temperature of the Earth's atmosphere linked to the<br> concentration of carbon dioxide?
    10·2 answers
  • How many grams are there in 6 moles of h2o?
    13·1 answer
  • Question: a group of similar organs doing the same job form the next step on the Ribbon of life which is
    9·1 answer
  • Graphite is a soft, dark material often used as a lubricant and to make pencil lead. Diamond is often a clear, hard crystal. Whi
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!