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soldi70 [24.7K]

3 years ago

14

Select all of the following that are physical changes A. turning a tin can into aluminum foil B. breaking a window into very tin

y pieces C. photosynthesis D. iron rusting and breaking apart E. crushing a can F. melting a can

1 answer:

Ede4ka [16]3 years ago

5 0

Answer:

A, B, E

Explanation:

thats just how it works

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Becky wanted to figure out what type of work would work the best for growing beans see you watered one with Coca-Cola one with l

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IV: type of liquid used to water the plant (coca-cola, lemonade, water)
DV: height of growth
Control: time grown, same temperature and location

8 0

2 years ago

The amount of matter in a object is referred as:

mestny [16]

Volume is the thing
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4 0

3 years ago

Which statement describes compounds?

Natasha2012 [34]

Answer:

C

Explanation:

4 0

2 years ago

A sample of pure calcium fluoride with a mass of 15.0 g contains 7.70 g of calcium. how much calcium is contained in 45.0 g of c

kolbaska11 [484]

In a sample of pure calcium fluoride of mass 15.0 g, 7.70 g of calcium is present. First convert the mass into number of moles as follows:

$n=\frac{m}{M}$

Here, m is mass and M is molar mass.

Molar mass of Ca is 40 g/mol, putting the values,

$n=\frac{7.70 g}{40 g/mol}=0.1925 mol$

Similarly, molar mass of $CaF_{2}$ is 78.07 g/mol thus, number of moles will be:

$n=\frac{15.0 g}{78.07 g/mol}=0.1921 mol$ .

Thus, 0.1921 mol of $CaF_{2}$ have 0.1925 mol of Ca, or 1 mole of $CaF_{2}$ will have approximately 1 mole of Ca.

Now, mass of Ca needs to be calculated in 45.0 g of $CaF_{2}$ . Converting mass into number of moles first,

$n=\frac{45.0 g}{78.07 g/mol}=0.5764 mol$

Thus, number of moles of Ca will also be 0.5764 mol, converting number of moles into mass,

$m=n\times M=0.5764 mol\times 40 g/mol=23.06 g$

Therefore, mass of Ca will be 23.06 g.

6 0

3 years ago

For alkyl halides used in SN1 and SN2 mechanisms, rank the leaving groups in order of reaction rate. You are currently in a rank

Alex777 [14]

Answer:

Iodide> Bromide > chloride > flouride

Explanation:

During a nucleophilic substitution reaction, a nucleophilie replaces another in a molecule.

This process may occur via an ionic mechanism (SN1) or via a concerted mechanism (SN2).

In either case, the ease of departure of the leaving group is determined by the nature of the C-X bond. The stronger the C-X bond, the worse the leaving group will be in nucleophilic substitution. The order of strength of C-X bond is F>Cl>Br>I.

Hence, iodine displays the weakest C-X bond strength and it is thus, a very good leaving group in nucleophillic substitution while fluorine displays a very high C-X bond strength hence it is a bad leaving group in nucleophilic substitution.

Therefore, the ease of the use of halide ions as leaving groups follows the trend; Iodide> Bromide > chloride > flouride

4 0

2 years ago