How does the temperature of water change when it is placed in a freezer and

Method that used to separate kerosine and water?

nata0808 [166]

You can use a separating funnel. The person will go the top and the water to the bottom.

7 0

4 years ago

When 0.42 g of a compound containing C, H, and O is burned completely, the products are 1.03 g CO2 and 0.14 g H2O. The molecular

Luda [366]

Answer: The empirical and molecular formula for the given organic compound is $C_2H_2O_4$ and $C_6H_4O_2$

Explanation:

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:

$C_xH_yO_z+O_2\rightarrow CO_2+H_2O$

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.

We are given:

Mass of $CO_2=1.03g$

Mass of $H_2O=0.14g$

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 1.03 g of carbon dioxide, $\frac{12}{44}\times 1.03=0.28g$ of carbon will be contained.

For calculating the mass of hydrogen:

In 18g of water, 2 g of hydrogen is contained.

So, in 0.14 g of water, $\frac{2}{18}\times 0.14=0.016g$ of hydrogen will be contained.

Mass of oxygen in the compound = (0.42) - (0.28 + 0.016) = 0.124 g

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{0.28g}{12g/mole}=0.023moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{0.016g}{1g/mole}=0.016moles$

Moles of Oxygen = $\frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=\frac{0.124g}{16g/mole}=0.00775moles$

Step 2: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.00775 moles.

For Carbon = $\frac{0.023}{0.00775}=2.96\approx 3$

For Hydrogen = $\frac{0.016}{0.00775}=2.06\approx 2$

For Oxygen = $\frac{0.00775}{0.00775}=1$

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H : O = 3 : 2 : 1

Hence, the empirical formula for the given compound is $C_3H_{2}O_1=C_3H_2O$

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is :

$n=\frac{\text{molecular mass}}{\text{empirical mass}}$

We are given:

Mass of molecular formula = 108.10 g/mol

Mass of empirical formula = 54 g/mol

Putting values in above equation, we get:

$n=\frac{108.10g/mol}{54g/mol}=2$

Multiplying this valency by the subscript of every element of empirical formula, we get:

$C_{(3\times 2)}H_{(2\times 2)}O_{(1\times 2)}=C_6H_4O_2$

Thus, the empirical and molecular formula for the given organic compound is $C_3H_2O$ and $C_6H_4O_2$

6 0

3 years ago

How you could use the scientific method to learn whether water really does take longer to boil if you are watching it.

Alenkasestr [34]

Answer:

Please find the detailed explanation below

Explanation:

A scientific method is a sequence of steps that is used to solve a problem. Every scientific method begins with a problem that needs to be solved.

Hence, in order to determine whether water really does take longer to boil if you are watching it, we employ the steps involved in a scientific method.

1) Ask a question/Make observation: This must initiate the process. The observation/question made here is that DOES WATER TAKE LONGER TIME TO BOIL WHEN WATCHED?

2. Formulating hypothesis; an hypothesis is a testable prediction of a possible solution to the stated problem. In this case, an hypothesis could read: IF water is watched while boiling, THEN it will take a longer time to boil. A hypothesis must be tested for it to be proved or disproved.

3. Test hypothesis: The formulated hypothesis is tested via conducting an experiment. The set up of the experiment can involve one group where water is boiled while watching it and another where water is boiled without watching. The former group is called Experimental group, while the latter group is called Control group. The time it takes for each group of water to boil will be recorded.

The independent variable (manipulated variable) will be the WATCHING, while the dependent variable (tested/responding variable) will be the TIME IT TAKES FOR WATER TO BOIL

4. Analyse the data; the data refers to the recorded time for each group of water. This will be analysed and compared.

5. Make conclusion; the conclusion depends on the result, which is the recorded time for each group of boiled water. Based on the result, the hypothesis can either be rejected or accepted. For example, if the control group boils faster than the experimental group, our hypothesis will be accepted but if otherwise, the hypothesis will be rejected.

Therefore, via the scientific method, it can be determined if it really takes longer time for water to boil while watched.

8 0

4 years ago

The Sun heats land and water, how is this related to wind and ocean currents?

Yuki888 [10]

Answer:

"The sun warms up parts of the oceans. Warm waters rise just like warm air rises. So, as the warmer ocean waters begin to rise in a particular area, the cooler ocean waters from a different area will move in to replace the warmer ocean waters, and this creates our ocean currents."

Explanation:

Hope this is helpful :)

8 0

3 years ago

Consider the following specific heats: copper, 0.384 J/g· ◦C; lead, 0.159 J/g· ◦C; water, 4.18 J/g· ◦C; glass, 0.502 J/g· ◦C. Wh

Roman55 [17]

Answer:

The correct answer is

2. Water

Explanation:

The specific heat capacity is the amount of heat required to raise the temperature of a unit mass of a substance by one degree. It is connected to the capacity of the substance to retain heat as well as the rate at which it will cool down or heat up when exposed to a specific amount of heat loss or heat supplied. A substance with a low heat capacity such as iron will cool down or heat up more quicker than a substance with a high heat capacity such as water.

From the list of substances water has the highest heat capacity, (4.18 J/g) as such it will retain heat for the longest period of time.

7 0

3 years ago