Standardized means that a specific amount EDTA is added to a specific volume of distilled water. Water hardness is determined by the the amount of a standard EDTA solution to change the color of the water from red to blue. For example if one added the correct amount of EDTA to twice the volume of distilled water the solution would be weak. Titration of the hard water would give a erroneous high result.
Answer:The Geocentric and the Heliocentric models are descriptions of the universe known at the time when these models were developed. The main difference between the two models is the perceived center of the known universe. According to the geocentric model, Earth is the center of the known universe
Explanation:I answerd the question before in Earth Science
Answer:
<h2>5.Solder........</h2><h3>Hope it helps you!!</h3>
Answer:
Explanation:
We are asked to find how many moles of sodium carbonate are in 57.3 grams of the substance.
Carbonate is CO₃ and has an oxidation number of -2. Sodium is Na and has an oxidation number of +1. There must be 2 moles of sodium so the charge of the sodium balances the charge of the carbonate. The formula is Na₂CO₃.
We will convert grams to moles using the molar mass or the mass of 1 mole of a substance. They are found on the Periodic Table as the atomic masses, but the units are grams per mole instead of atomic mass units. Look up the molar masses of the individual elements.
- Na: 22.9897693 g/mol
- C: 12.011 g/mol
- O: 15.999 g/mol
Remember the formula contains subscripts. There are multiple moles of some elements in 1 mole of the compound. We multiply the element's molar mass by the subscript after it, then add everything together.
- Na₂ = 22.9897693 * 2= 45.9795386 g/mol
- O₃ = 15.999 * 3= 47.997 g/mol
- Na₂CO₃= 45.9795386 + 12.011 + 47.997 =105.9875386 g/mol
We will convert using dimensional analysis. Set up a ratio using the molar mass.
We are converting 57.3 grams to moles, so we multiply by this value.
Flip the ratio so the units of grams of sodium carbonate cancel.
The original measurement of moles has 3 significant figures, so our answer must have the same. For the number we found that is the thousandth place. The 6 in the ten-thousandth place to the right tells us to round the 0 up to a 1.
There are approximately <u>0.541 moles of sodium carbonate</u> in 57.3 grams.
Answer:
hope this helps <3
Explanation:
Landon glances across the dinner table and thinks to himself that his fathers curly hair looks just like his own. He wishes his hair were straight like his mothers because he thinks he looks better with straight hair. Landon works hard to keep it straighter by combing and using hair gel, but it usually curls right back up. He has his mothers nose, but not her hair, unlike his sister Emily, who is also the result of the combination of the DNA from both of his parents and has straight hair like their mothers. Most eukaryotic organisms, like Landon, are formed through the process of sexual reproduction. Landon realizes that he and Emily are evidence that sexual reproduction, the combination of their two parents, creates diverse offspring.
Landons dinner plate is filled with one of his favorite foods-mashed potatoes made from potatoes fresh from his grandmothers garden. He remembers helping her get ready to plant the potatoes in early spring. They cut each potato into several pieces and planted the pieces in a nice straight row in the garden. When these eukaryotic plants came up, he noticed that each plant looked like all the others. These identical offspring with uniform traits are the result of asexual reproduction. Landons grandmother grew potatoes by cutting the whole potato into smaller pieces, which is a type of asexual reproduction called vegetative propagation.
After dinner, Landon wanted to go watch television, but his mother insisted that he put the leftover food in the refrigerator. Perhaps she knew that the cool temperature inside the refrigerator would stop the growth of bacteria, which are prokaryotic and can reproduce asexually in as little as 20 minutes. This rapid asexual reproduction, called binary fission, would produce thousands and thousands of identical bacterial cells that could cause Landons tasty leftover food to spoil before the end of his favorite show.
Landon finishes up the dishes and puts away the leftovers. As he sets the last dinner glass back into the cupboard, he catches a glimpse of his curly hair in his reflection. He thinks to himself that his mothers nose and his fathers hair are actually a good combination that looks pretty good on him
