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TEA [102]
2 years ago
5

Which step in the Scientific Method should be done after asking a question and before developing a hypothesis? A)analyze the dat

a
B)communicate findings
C) conduct background research D)design an experiment​
Chemistry
2 answers:
Alexxx [7]2 years ago
6 0
I believe the best answer for this would be D) no matter what it can be A or B and C wouldn’t make much sense so D) design an experiment
zysi [14]2 years ago
5 0
This is so frustrating I don’t even understand this
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The reaction of Pb+4 and O-2 produces the compound of
vovikov84 [41]

Answer:

Pb₂O₄

                               

Explanation:

The given species are:

        Pb⁴⁺               O²⁻  

Now, to solve this problem, we use the combining powers which corresponds to the number of electrons usually lost or gained or shared by atoms during the course of a chemical combination.

                                          Pb⁴⁺               O²⁻  

Combining power               4                    2

Exchange of valencies        2                    4

Now the molecular formula is  Pb₂O₄

                               

4 0
2 years ago
Anything in red is the question
laila [671]

Answer:

  • Question 19: the three are molecular compounds.
  • Question 20: CuSO₄.5H₂O

Explanation:

<em>Question 19.</em>

  • C₂H₄
  • HF
  • H₂O₂

All of them are the combination of two kinds of different atoms in fixed proportions.

  • C₂H₄: two carbon atoms per four hydrogen atoms
  • HF: one hydrogen atom per one fluorine atom
  • H₂O₂: two hydrogen atoms per two oxygent atoms

Thus, they all meet the definition of compund: a pure substance formed by  two or more different elements with a definite composition.

Molecular compounds are formed by covalent bonds and ionic compounds are formed by ionic bonds.

Two non-metal elements, like H-F, C - C, C - H, H-O, H - H, and O - O will share electrons forming covalent bonds to complete their valence shell. Thus, the three compounds are molecular and not ionic.

<em>Question 20. </em>Formula of copper(II) sulfate hydrate with 36.0% water.

Copper(II) sulfate is CuSO₄. Its molar mass is 159.609g/mol

Water is H₂O. Its molar mass is 18.015g/mol

Calling x the number of water molecules in the hydrate, the percentage of water is:

       \dfrac{18.015x}{18.015x+159.609}=36\%\\ \\ \\ \dfrac{18.015x}{18.015x+159.609}=0.36

From which we can solve for x:

      18.015x=6.4854x+57.45924\\ \\ 11.5296x=57.45924\\ \\ x\approx4.98\approx5

Thus, there are 5 molecules of water per each unit of CuSO₄, and the formula is:

  • CuSO₄.5H₂O
4 0
3 years ago
How many moles of sodium (Na) are there in a<br> sample of 5.87 x 1024 atoms of sodium?
Leno4ka [110]
9.74x 2351 that's the answer
6 0
3 years ago
A mixture of gases containing 0.20 mol of SO2 and 0.20 mol of O2 in a 4.0 L flask reacts to form SO3. If the temperature is 25ºC
diamong [38]

Answer : The pressure in the flask after reaction complete is, 2.4 atm

Explanation :

To calculate the pressure in the flask after reaction is complete we are using ideal gas equation.

PV=n_TRT\\\\P=(n_1+n_2)\times \frac{RT}{V}

where,

P = final pressure in the flask = ?

R = gas constant = 0.0821 L.atm/mol.K

T = temperature = 25^oC=273+25=298K

V = volume = 4.0 L

n_1 = moles of SO_2 = 0.20 mol

n_2 = moles of O_2 = 0.20 mol

Now put all the given values in the above expression, we get:

P=(0.20+0.20)mol\times \frac{(0.0821L.atm/mol.K)\times (298K)}{4.0L}

P=2.4atm

Thus, the pressure in the flask after reaction complete is, 2.4 atm

5 0
3 years ago
Why isn't the Liter a basic SI unit of measurement? (In your answer use at least one SI base unit of measurement and one other d
Y_Kistochka [10]

Answer:

What give me a few minutes I have to finish my test them I will answer in comments.

5 0
3 years ago
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