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liq [111]
3 years ago
5

What investigations never involve hypotheses?

Chemistry
2 answers:
marshall27 [118]3 years ago
5 0
The correct answer is a descriptive investigation.

An investigation which does not involve hypotheses called descriptive investigation.
Hypotheses are termed as scientific hypotheses and require that one can test it. In hypothesis, previous observation can not satisfactorily be explained with an available scientific theory.
Working hypotheses are being proposed for further research.
Hatshy [7]3 years ago
5 0
The investigation that never involves a hypothesis is: a descriptive investigation. these investigations are used when little is known about a topic so you can't form a hypothesis. i hope this helps!
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The total number of sodium atoms in 46.0 grams of sodium<br> is
marusya05 [52]
The answer is 2.0, and it is because
3 0
3 years ago
Balance the following redox equations by the ion-electron method:? A) H2O2 + Fe 2+ ---&gt; Fe 3+ + H2O (in the acidic solution)
Vaselesa [24]
We balance the given reactions above by following the rules in balancing redox reactions in acidic or basic solutions. Balance the atoms aside from the O and H atoms. Then we balance the Os and Hs by adding H2O or H+. Finally, we balance the total charge of the reactant and product by adding e-. We do as follows:

<span>A) H2O2 + Fe 2+ ---> Fe 3+ + H2O (in the acidic solution)
</span><span>   2H+ + </span>H2O2 + Fe 2+ ---> Fe 3+ + 2H2O 
   e- + 2H+ + H2O2 + Fe 2+ ---> Fe 3+ + 2H2O 
<span>
C) CN- + MnO4- ---> CNO- +MnO2 (in basic solution)
</span>     CN- + MnO4- ---> CNO- +MnO2 + H2O
     2H+ + CN- + MnO4- ---> CNO- +MnO2 + H2O
     2OH- + 2H+ + CN- + MnO4- ---> CNO- +MnO2 + H2O + 2OH-
     2H2O + CN- + MnO4- ---> CNO- +MnO2 + H2O + 2OH-
     e- + H2O + CN- + MnO4- ---> CNO- +MnO2 + 2OH-
<span>
E) S2O2/3- + I2 ---> I- + S4O2/6- (in acidic solution)
    2</span>S2O2/3- + I2 ---> 2I- + S4O2/6- 
    4H+ + 2S2O2/3- + I2 ---> 2I- + S4O2/6- + 2H2O
    6e- + 4H+ + 2S2O2/3- + I2 ---> 2I- + S4O2/6- + 2H2O

3 0
4 years ago
Three isotopes of oxygen are oxygen-16 oxygen-17 and oxygen-18. Write the symbol for each, including the atomic number and mass
Karo-lina-s [1.5K]
The symbol of an isotope is:
^A _Z X
A - the mass number
Z - the atomic number
X - the symbol of an element

The symbol of oxygen is O.

The atomic number is the same for all isotopes of one element. For oxygen it's 8, because every atom of oxygen has 8 protons in its nucleus.

The mass number is the number of nucleons (protons + neutrons) in the nucleus of an atom, and it's given in the name of an isotope. Oxygen-16 has the mass number 16, oxygen-17 has the mass number 17, oxygen-18 has the mass number 18.

Oxygen-16: ^{16} _8 O

Oxygen-17: ^{17} _8 O

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5 0
3 years ago
Calcium carbonate decomposes at high temperatures to give calcium oxide and carbon
Dafna1 [17]

Answer:

Explanation:

Calcium carbonate decomposes at high temperatures to give calcium oxide and carbon

dioxide as shown below.

CaCO3(s) = CaO(s) + CO2(g)

The Kp for this reaction is 1.16 at 800°C. A 5.00 L vessel containing 10.0 g of CaCO3(s)

was evacuated to remove the air, sealed, and then heated to 800°C. Ignoring the volume

occupied by the solid, what will overall mass percent of carbon in the solid once equilibrium is reached?

4 0
2 years ago
The water in a 2500-L aquarium contains 1.25 g of copper. Calculate the concentration of copper in the water in ppm (remember 1
lorasvet [3.4K]

Answer:

0.5ppm

Explanation:

Step 1:

Data obtained from the question.

Volume of water = 2500L

Mas of Cu = 1.25 g

Step 2:

Determination of the concentration of Cu in g/L. This is illustrated below:

Volume of water = 2500L

Mas of Cu = 1.25 g

Conc. of Cu In g/L =?

Conc. g/L = Mass /volume

Conc. of Cu in g/L = 1.25/2500

Conc. of Cu in g/L = 5x10^–4 g/L

Step 3:

Conversion of the concentration of Cu in g/L to ppm. This is illustrated below

Recall:

1g/L = 1000mg/L

Therefore, 5x10^–4 g/L = 5x10^–4 x 1000 = 0.5mg/L

Now, we know that 1mg/L is equal to 1ppm.

Therefore, 0.5mg/L is equivalent to 0.5ppm

6 0
3 years ago
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