Answer: There are five signs of chemical change
- Color Change
- Production of an odor
- Change of Temperature
- Evolution of Gas (bubbles start to form)
- Precipitate (starts to form a solid)
When these signs start to form you know chemical change is at work.
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Answer: Option E. There are covalent bonds between the hydrogen atoms
Explanation:
Answer:
11 molecules of CH4.
23 atoms of C is the leftover.
Explanation:
Hello!
In this case, for the formation of methane:
We can see there is an excess of carbon based on their stoichiometry, because the needed amount of hydrogen gas molecules would be:
Thus, the formed molecules of methane are computed below:
In such a way, the leftover of carbon atoms are:
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The freezing point depression is calculated through the equation,
ΔT = (kf) x m
where ΔT is the difference in temperature, kf is the freezing point depression constant (1.86°C/m), and m is the molality. Substituting the known values,
5.88 = (1.86)(m)
m is equal to 3.16m
Recall that molality is calculated through the equation,
molality = number of mols / kg of solvent
number of mols = (3.16)(1.25) = 3.95 moles
Then, we multiply the calculated amount in moles with the molar mass of ethylene glycol and the answer would be 244.9 g.
Answer:
A. 0.90 L.
Explanation:
- NaOH solution will react with H₂SO₄ according to the balanced reaction:
<em>H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O.</em>
<em>1.0 mole of H₂SO₄ reacts with 2.0 moles of NaOH.</em>
- For NaOH to react completely with H₂SO₄, the no. of millimoles should be equal.
<em>∴ (MV) NaOH = (xMV) H₂SO₄.</em>
x for H₂SO₄ = 2, due to having to reproducible H⁺ ions.
<em>∴ V of NaOH = (xMV) H₂SO₄/ M of NaOH</em> = 2(0.6 L)(3.0 M)/(4.0 M) = <em>0.90 L.</em>
