Answer:
hair is a physical change.
Cooking is a physical and chemical change.
Ice cream melting in the sun is a physical change.
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Empirical formula is the simplest formula showing the simplest ratio of atoms in a compound. Calculated as shown;
we start by calculating the number of moles of each atom;
moles of nickel = 9.11 g ÷ 58.7 g = 0.155 moles
moles of fluorine = 5.89 g ÷ 19 g = 0.31 moles
Then we get the ratio of the moles of nickel to that of flourine
That is 0.155 : 0.31 (dividing by the smallest)
0.155/0.155 : 0.31/0.155
we get 1:2 ( the simplest ratio)
Therefore the empirical formula is nif2
Answer:
e. T₂= 4T₁
Explanation:
Initially, we have a number of moles (n₁) a gas sample at a certain pressure (P), temperature (T₁) and volume (V). We can relate these variables through the ideal gas equation.
P . V = n₁ . R . T₁
where,
R is the ideal gas constant
We can rearrange this equation like:
If only one fourth of the initial molecules remain n₂ = 1/4 n₁. The new temperature (T₂) assuming pressure and temperature remain constant is:
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Answer:
There are 255, 85 grams of Strontium in 2,92 moles.
Explanation:
We perform a simple rule of three to calculate the number of grams, knowing that one mole of Sr weights 87, 62 grams:
1 mol Sr---------87, 62 grams
2,92 mol Sr-----x=(2,92 mol Sr x-87, 62 grams)/1 mol Sr= 255,8504 grams
