Answer:
They use hypotheses to guess a result based on what they already know. Observations are used to record the results of an experiment. Predictions are used to have an expected outcome of a test, thinking the hypothesis is correct. Experiments are used to test the hypothesis.
Answer:
6.25 μg/mL
Explanation:
When a dilution is made, the mass of the solute is conserved (Lavoiser's law), so the mass pipetted will be the mass in the assay. The mass is the concentration (C) multiplied by the volume (V). If the pipet solution is called 1, and the assay 2:
m1 = m2
C1*V1 = C2*V2
C1 = 250 μg/mL
V1 = 25 μL
V2 = 975 μL + 25 μL = 1000 μL (is the final volume of the assay after the addition of LDH)
250*25 = C2*1000
C2 = 6.25 μg/mL
Answer: ice is less dense than liquid water. If ice was more dense, Earth would freeze.
Explanation: There are many reasons why life on Earth depends on the characteristics of water. One could discuss hydrogen bonds and its role as a solvent, but the unusual property of water is is the change in density with change in temperature. Water is densest at 4 degC, which is why ice floats - it is less dense than cold water (it melts quickly in warm water, so density isn’t impotant at higher temperatures). Most liquids are less dense than the solid, frozen form. If this was the case with water, any ice that formed would sink, and sease would freeze from the bottom up. Furthermore, the lowest layers would be insulated and would not all melt in summer. Thus over time, the seas would become a thin layer of liquid water at best, over solid ice. Life could not develop without liquid seas. In addition, ice is reflective, reducing the amount of sunlight absorbed, further reducing temperatures. Without ocean circulation, polar areas would be even colder, and there would be no rain.
Using this equation, we can take 25/(1.0 + 19) and find that it is equal to 1.25 moles.
Answer:
Chemical reaction B, because the product is a compound
Explanation:
A synthesis or combination reaction is that reaction that involves combination of two or more reactants to form a single product. The two or more reactants are often elements that chemically combine to form a single compound.
In this question, two chemical reactions are involved in which chemical reaction A has 1 reactants and 3 products while chemical reaction B has 2 reactants and 1 product. Based on the explanation above, the reaction B correctly identifies the synthesis reaction because the single product is a compound.
