Answer:
Explanation:
<u>1. Convert Atoms to Moles</u>
We must use Avogadro's Number: 6.022*10²³. This is the number of particles (atoms, molecules, ions, etc.) in 1 mole of a substance. In this case, the particles are atoms of helium. We can create a ratio.
Multiply by the given number of helium atoms.
Flip the fraction so the atoms of helium cancel.
<u>2. Convert Moles to Grams</u>
We must use the molar mass, which is found on the Periodic Table.
Use this as a ratio.
Multiply by the number of moles we calculated. The moles will then cancel.
<u>3. Round </u>
The original measurement has 3 significant figures (5, 5, and 0). Our answer must have the same. For the number we calculated, it is thousandth place. The 3 in the ten thousandth place tells us to leave the 5.
The mass is <u>0.365 grams of helium</u> so choice A is correct.
Answer: This is simple, if it has a high flammability, and you light it on fire, then that would be a chemical change.
Explanation:
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Answer: Molarity is defined as moles of solute per liter of solution. So, find the moles of solute and divide by the liters of solution.
molar mass AlCl3 = 133g/mole
moles AlCl3 = 127 g x 1 mole/133 g = 0.955 moles
liters of solution = 400 ml x 1 liter/1000 ml = 0.400 liters
Molarity = 0.955 moles/0.400 liters = 2.39 M
Explain: I looked it up on wyzant.com
heat is transferred from your hand to the ice cube
The physical properties of alkenes and alkynes are generally similar to those of alkanes or cycloalkanes with equal numbers of carbon atoms. Alkynes have higher boiling points than alkanes or alkenes, because the electric field of an alkyne, with its increased number of weakly held π electrons, is more easily distorted, producing stronger attractive forces between molecules.
