Answer:
Explanation:
Accuracy is defined is as the ability to perfectly repeat results in an experiment. It is simply reproducing the same set of result with little to no altercation.
Precision is nearness of the result to the true value.
(a) Checking for consistency in the weight of chocolate chip cookies: 17.27 g, 13.05 g, 19.46 g, 16.92 g
The result above is neither accurate nor precise. We can see a lot of inconsistencies in the readings shown and no repeatability whatsoever.
(b) Testing the volume of a batch of 25- mL pipettes: 27.02mL, 26.99 mL, 26.97 mL, 27.01 mL
The results here are accurate but not precise. They are a little bit off the 25mL mark but the experiment was able to reproduce nearly the same result.
(c)Determining the purity of gold: 99.9999%, 99.9998%, 99.9999%
This result is both precise and accurate. Pure Gold should be 100% and our values are very close. The experiment also was able to generate very accurate results.
I believe the answer is C.
Answer:
Valence electrons
Explanation:
The formation of phosphorus trifluoride is orchestrated by the sharing of the valence electrons between phosphorus and fluorine.
This is called covalent bonding. In covalent bonding, elements with zero or very small electronegativity combines together. Such bonding occurs between non-metals.
For this bond to form, phosphorous shares its 5 electrons with the 3 of the fluorine.
The balanced equation is 
.
The above equation is a redox reaction. A chemical equation is said to be balanced when the total mass of atoms on the reactant and product side are equal. This means that the number of atoms on both side must also be equal.
We have, 
.
The number of atoms of Calcium (one on both sides) and Hydrogen(four on both sides) are equal. Whereas, there are 2 atoms of Oxygen on the right-hand side and only 1 atom of Oxygen on the left-hand side. So, we can put the coefficient of 2 on the molecule that has Oxygen on the left-hand side to balance them out. i.e.,
Now, there are 6 atoms of Hydrogen on the left-hand side but only 4 on the right-hand side. To balance this, we can put the coefficient of 2 on the Hydrogen molecule on the right-hand side.
Thus, we get the final balanced equation as :
To read about balancing chemical equations visit brainly.com/question/11904811
Answer:
A Chemical reaction involves changes in energy in the form of absorbtion and release of heat due to the formation and breakdown of chemical bonds. A chemical reaction is categoried as endothermic reaction in which heat energy is take in or absorbed and exothermic reaction in which energy is released.
<u>A model can be created by following below details:</u>
- Take a beaker and put 10 milliliters of vinegar in it.
- Place a thermometer in the beaker and measure the initial temperature.
- Then add half teaspoon of baking soda, that results into decreasing in the temperature.
So, the decrease in temperature shows it is an endothermic reaction in which heat energy is absorbed.
