Answer and Explanation:
- <em>Computers ( The computers are very old and very slow, and we have to notice that almost everyone are using computers at the same time at the school, which makes it even harder for it to load up assignments. )</em>
- <em>The Rick Rolling ( Everyone keeps sending links to teachers and students saying that it is part of some assignment but then you have to listen to Rick Astley, they should really block these links. )</em>
- <em>The lockers ( The lockers are also very old and they are breaking down and rusting a lot from the moisture in the hallways. One of the lockers even broke down today!!! I hope they can fix this so no one else gets hit with a locker door. )</em>
<em>Hope this helps! ;)</em>
Answer:
Explanation:acid etching
etching
the cutting of a hard surface such as metal or glass by a corrosive chemical, usually an acid, in order to create a design.
etching - etching of dental enamel with an acid in order to roughen the surface, increase retention of resin sealant, and promote mechanical retention.
acid etching
microscopic roughening of dental enamel with an acid (usually phosphoric acid) to remove the smear layer and open enamel tubules, increase retention of resin sealant, and promote mechanical retention.
acid etching Dentistry
The application of a weak acid—e.g., 30% phosphoric acid—to the surface of enamel to roughen the surface of a tooth before bonding a resin or veneer; acid etching increases mechanical retention, cleans the enamel and improves the wetting of resins. See Cosmetic dentistry.
Answer:
Explanation:
1 mole of any substance contains the same number of particles. The particles can vary (atoms, molecules, formula units), but there are always 6.022*10²³ particles. In this case, the particles are formula units of potassium nitrate or KNO₃.
Let's create a ratio.
Since we are trying to find the formula units in 0.250 moles, we multiply by that number.
The units of moles of potassium nitrate cancel.
The denominator of 1 can be ignored, so we can make a simple multiplication problem.
If we round to the nearest tenth, the 0 in the hundredth place tells us to leave the 5 in the tenth place.
0.250 moles of potassium nitrate is approximately equal to 1.5*10²³ formula units of potassium nitrate and choice B is correct.
Answer:
B). An Experiment that tests the hypothesis.
Explanation:
The element that is missing from Yasir's scientific investigation is 'an experiment which tests a hypothesis.' His experiment does not provide a verifiable statement revealing his proposition or prediction regarding the possible outcome of the experiment which could be verified by using a research or investigation. He rather tests his proposition indirectly by asking 'which color they like better' and using it to make an educated guess. Thus, <u>option B</u> is the correct answer.
