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marissa [1.9K]
4 years ago
15

CAN ANYONE ELP ME WITH CHEMISTRY PLEASE?? I will be asking multiple questions but even if you can only answer one-- I will still

deeply appreciate it!!! (These are the one's Im unsure about..)
3. Identify the reducing agent in the following equation: 2 Al(s) + 3 H2SO4 (aq) arrow Al2(SO4)3 (aq) + 3 H2 (g).

A. Al (s) *
B. H2SO4 (aq)
C. Al2(SO4)3 (aq)
D. H2 (g)

9. How many milliliters are 0.200 M HCl are required to react completely with 25.0 milliliters of 0.100 M methylamine, CH3NH2?

A. 5.00 ml
B. 6.25 ml
C. 12.5 ml *
D. 25.0 ml

16. A solution has a [OH−] of 1 x 10−9. What is the pOH of this solution?

A. 5
B. 7
C. 9 *
D. 12

17. If a small amount of excess acid is added to a buffered solution, the pH of the solution should:

A. change sharply and then neutralize *
B. remain very close to the original pH value
C. fluctuate rapidly between high and low values and then achieve a neutral balance
D. neutralize instantaneously

18.Compared to other main group hydrides, such as CH4, NH3, H2S and HF, water is unique because it is a liquid at room temperature. The most likely explanation for this is that:

A. Water is more plentiful than any of these other compounds.
B. Water contains oxygen and since oxygen has a high boiling point, so should water.
C. Water's structure allows for the formation of multiple hydrogen bonds with other molecules, including itself. *
D.Water is able to dissolve nonpolar gases like oxygen and carbon dioxide.

28. Predict whether the following double-replacement reaction will produce a precipitate: MgCl2 + Li2CO3 arrow MgCO3 + 2 LiCl.

A.No; all products are soluble
B. Yes; the MgCO3 will precipitate *
C.Yes; the LiCl will precipitate
D. Yes; both the MgCO3 and the LiCl will precipitate

BTW I added a * to the answers I THINK are correct.
Chemistry
1 answer:
vlabodo [156]4 years ago
6 0
3, 9, 16 are correct! 17 should be b because buffered means that it resists change in pH
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An alcohol with molecular formula CnH2n+1OH has a chiral carbon atom but does not react with
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In general, the given alcohol above belongs to tertiary, and this is the reason why it doesn't undergo oxidation. Now, if you will try to analyze the given molecular formula, you will end up having seven (7) carbon atoms which make up a chiral carbon. So the answer would be option C. Hope that answer helps.
5 0
4 years ago
Hydrofluoric acid (HF) can be prepared according to the following equation:
Artemon [7]

Given the balanced equation:

( Reaction type : double replacement)

CaF2 + H2SO4 → CaSO4 + 2HFI

We can determine the number of grams prepared from the quantity of 75.0 H2SO4, and 63.0g of CaF2 by converting these grams to moles per substance.

This can be done by evaluating the atomic mass of each element of the substance, and totaling it to find the molecular mass.

For H2SO4 or hydrogen sulfate it's molecular mass is the sum of the quantity of atomic mass per element. H×2 + S×1 + O×4 = ≈1.01×2 + ≈32.06×1 + ≈16×4 = 2.02 + 32.06 + 64 = 98.08 u (Dalton's or Da) or g / mol.

For CaF2 or calcium fluoride, it's molecular mass adds 1 atomic mass of calcium and 2 atomic masses of fluoride due to the number of atoms.

Ca×1 + F×2 = ≈40.07×1 + ≈19×2 = 40.08 + 38 = 78.07 u (Da or Dalton's) or g / mol.

3 0
3 years ago
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What is the predicted outcome for very low mass stars (those that are smaller than about the mass of the sun)?
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Answer:

In case of low-mass stars,the outer layers of the low mass stars are expelled  as the core collapses such that the outer layers form a planetary nebula.

Explanation:

In case of low-mass stars,the outer layers of the low mass stars are expelled  as the core collapses such that the outer layers form a planetary nebula. The core remains as a white dwarf and finally become a black dwarf as it cools down. A low mass star consumes its core hydrogen and turns it into helium over its lifetime.

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7 0
3 years ago
If a sample of copper is 215g, how many moles of copper atoms are in the sample?
shusha [124]

Answer:

3.38 moles.

Explanation:

The following data were obtained from the question:

Mass of copper (Cu) = 215 g

Number of mole of copper (Cu) =...?

The number of mole of copper (Cu) in 215 g can be obtained as follow:

Mass of copper (Cu) = 215 g

Molar mass of copper (Cu) = 63.55 g/mol

Number of mole of copper (Cu) =...?

Mole = mass /Molar mass

Mole of Cu = 215/63.55

Mole of Cu = 3.38 moles

Therefore, 3.38 moles of copper (Cu) is present in the sample.

6 0
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