Answer:
CaCO3 + 2HCl ---> CaCl2 + H2O + CO2
Explanation:
The reaction between solid calcium carbonate and a mineral acid such as aqueous HCl is a neutralization reaction and occurs with the evolution of CO2 gas.
The balanced equation is given below
CaCO3 + 2HCl ---> CaCl2 + H20 + CO2
The product CaCl2 is water soluble which accounts for why the stain is removed, while CO2 gas escapes away from the reaction surface.
<span>12.4 g
First, calculate the molar masses by looking up the atomic weights of all involved elements.
Atomic weight manganese = 54.938044
Atomic weight oxygen = 15.999
Atomic weight aluminium = 26.981539
Molar mass MnO2 = 54.938044 + 2 * 15.999 = 86.936044 g/mol
Now determine the number of moles of MnO2 we have
30.0 g / 86.936044 g/mol = 0.345081265 mol
Looking at the balanced equation
3MnO2+4Al→3Mn+2Al2O3
it's obvious that for every 3 moles of MnO2, it takes 4 moles of Al. So
0.345081265 mol / 3 * 4 = 0.460108353 mol
So we need 0.460108353 moles of Al to perform the reaction. Now multiply by the atomic weight of aluminum.
0.460108353 mol * 26.981539 g/mol = 12.41443146 g
Finally, round to 3 significant figures, giving 12.4 g</span>
Units of measurement are the terms that we use to describe the size of something. You probably know that units include things like seconds, kilograms, meters, and so forth.
Without standard units of measurement, scientists would have a huge problem understanding what other scientists were saying. After all, if I were to refer to a meter as "the length of my leg" and another scientists were to refer to it as "the length of a Saint Bernard dog", we'd have a lot of trouble when it came to do actual science. To avoid this problem, the SI system of units gives us a convenient and, more importantly, standard set of units that we can agree on.
Answer:
6.It is concluded that while high temperature has an unfavourable effect on seed set of radish plants, it also weakens the incompatibility reaction between pollen and style, so that the result is a small increase in yield.
7.The result of the study showed that music with a higher intensity is more distracting and has a greater effect on task performance and concentration. The result helped formulate the Attention Drainage Effect theory, which is based on Kahneman's (1973) capacity model of attention
8. If the food is more colorful then the fish will eat more because they're more interested in the colors
9.If plants do not receive enough light, they will not grow at their maximum rate or reach their maximum potential, regardless of how much of any other variable – water, growth medium or fertiliser – they receive. Light is the driving force for photosynthesis, a plant process that changes sunlight into chemical energy. Plants need five things in order to grow: sunlight, proper temperature, moisture, air, and nutrients. These five things are provided by the natural or artificial environments where the plants live. If any of these elements are missing they can limit plant growth.
The independent (or manipulated) variable is something that the experimenter purposely changes or varies over the course of the investigation. The dependent (or responding) variable is the one that is observed and likely changes in response to the independent variable.
10.What effect does smiling have on a teacher giving no homework.
Hypothesis
If a student smiles at teacher, then no homework will be assigned
independent variable is smiling
dependent variable is homework
Explanation:
