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3 years ago

Which tasks can be used to start a descriptive investigation

Chemistry

2 answers:

Rainbow [258]3 years ago

8 0

Answer:

The tasks which form the preliminaries to a descriptive investigation are: Making careful objective observations. Asking the relevant scientific questions.

9966 [12]3 years ago

4 0

The tasks which form the preliminaries to a descriptive investigation are: Making careful objective observations. Asking the relevant scientific questions

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Air is a mixture state three reasons

Natasha_Volkova [10]

1. different gases mix together to form air and no new comound is formed
2. air has variable composition
3. air shows the properties of its constituent substances

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3 years ago

If the average atomic mass of Rhodium is 102.91 amu, which isotope do you think has the greater percent abundance?

Illusion [34]

round up given mass to a whole number

$\\ \sf\longmapsto 102.91$

$\\ \sf\longmapsto 102.9$

$\\ \sf\longmapsto 103$

Hence our answer is Rhodium-103

8 0

3 years ago

Round off or add zero to the following calculated answers to give a final answer with three significant figures: 3.528x10exponen

Readme [11.4K]

352.8
with this all you have to do is move the decimal point to the right 2 times.

5 0

4 years ago

How many molecules are in 1.75 moles of Caco3?

saw5 [17]

Answer:

1.054 x 10²⁴ molecules

Explanation:

In order to convert moles of any given substance into a number of molecules, we need to use Avogadro's number, which states the number of molecules -or atoms, in the case of elements- present in one mol:

In one mol there are 6.023x10²³ molecules.

We now convert 1.75 moles into molecules:

1.75 mol * 6.023x10²³ molecules/mol = 1.05x10²⁴ molecules

5 0

3 years ago

The solubility of acetanilide is 12.8 g in 100 mL of ethanol at 0 ∘C, and 46.4 g in 100 mL of ethanol at 60 ∘C. What is the maxi

weqwewe [10]

Answer: 72.41% and 26.90% respectively.

Explanation:

At 60°C, you can dissolve 46.4g of acetanilide in 100mL of ethanol. If you lower the temperature, at 0°C, you can dissolve just 12.8g, which means (46.4g-12.8g)=33.6g of acetanilide must have precipitated from the solution.

We can calculate recovery as:

$\%R=\frac{crystalized\ mass}{initial\ mass}*100 =\frac{33.6\ g}{46.4\ g}*100=72.41\%$

So the answer to the first question is 72.41%.

For the second part just use the same formula, the mass of the precipitate is the final mass minus the initial mass, (171mg-125mg)=46mg.

$\%R=\frac{crystalized\ mass}{initial\ mass}*100 =\frac{46\ mg}{171\ mg}*100=26.90\%$

So the answer to the second question is 26.90%.

3 0

3 years ago