Considering the definition of percentage by mass, the mass percentage of CaCO₃ is 68.59%.
<h3>What is mass percentage</h3>
The percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.
In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.
The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

<h3>Mass percentage of CaCO₃</h3>
In this case, you know:
- mass of CaCO₃: 2.62 grams
- mass of limestone: 3.82 grams
Replacing in the definition of mass percentage:

<u><em>mass percentage= 68.59 %</em></u>
Finally, the mass percentage of CaCO₃ is 68.59%.
Learn more about percentage by mass:
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The formula we can use here is the Plancks equation:
E = h c / ʎ
where h is Plancks constant = 6.626 × 10-34 m2 kg / s, c
is speed of light = 3 x 10^8 m/s and ʎ is wavelength = 656.1 x 10^-9 m
Therefore E is:
E = (6.626 × 10-34 m2 kg / s)
* (3 x 10^8 m/s) / 656.1 x 10^-9 m
<span>E = 3.03 x 10^-19 J</span>
Answer:
Redox reaction and single displacement
Explanation:
This reaction is first of all a redox reaction. A redox reaction is a reaction that involves both oxidation and reduction. Oxidation involves increase in oxidation number while reduction involves decrease in oxidation number.
Copper (Cu) had an oxidation number of "0" as a reactant but had an oxidation number of "2+" in the product [Cu(NO₃)₂] hence oxidation occurred.
Nitrogen (N) had an oxidation number of "5+" in the reactant (HNO₃) but had an oxidation number of "4+" in the product (NO₂) hence reduction also occurred.
Also, from the reaction, it can be deduced that copper (Cu) displaced hydrogen (H) from the nitric acid (HNO₃) solution to form copper (II) nitrate [Cu(NO₃)₂]. It should be noted that copper can displace hydrogen because it is higher than hydrogen in the electrochemical series. Hence, this reaction can also be called a single displacement reaction. A single displacement reaction is a reaction in which an atom of an element replaces another atom in a compound (as seen in the equation given in the question).
An Ionic bond is when you have a metal and a nonmetal element bonded together. In this kind of bonds, the metal atom takes electrons from the nonmetal. on other words, this bond involves the gaining and losing of electrons. The atom that receives the electrons becomes an anion (negatively charged ion) and the one that loses them becomes the cation (positively charged ion)
A covalent bond is a bond created between two nonmetals element. In here, both atoms share the electrons.
Both bonds involve interaction between atoms.
Answer:
Independent variable: DIFFERENT TEMPERATURE
Explanation:
The independent variable of an experiment is the variable that the experimenter changes or manipulates in order to effect an outcome or response in the measured variable/dependent variable.
In this experiment, a scientist wants to determine how temperature affects photosynthesis. He sets up the experiment by adding 20ml of water at different temperatures to three test tubes. Hence, the independent or experimental variable is the DIFFERENT TEMPERATURES GIVEN TO EACH PLANTS IN THE TEST TUBE because it is what the experimenter changes in order to effect a measurable outcome i.e. oxygen released in each balloon as a result of photosynthesis, which is the dependent variable