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4 years ago

1. What is energy measured in? 2. What should you consider when choosing which food you eat each day? 3. Name some energy stores

Chemistry

1 answer:

Serggg [28]4 years ago

8 0

Answer:

1. energy is measured in joule 2. the nutritional value of the food. 3. sources of energy are hydroelectric power, dry cell ,.dynamos

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Would you be able to fit a mole of rice in a 30.0m*8.5m*3.5m room??

Julli [10]

Answer:

No.

Explanation:

1. Volume of a rice grain

There is no standard for the size of a rice grain, so let's make an arbitrary assumption.

An average rice grain behaves as if it were a rectangular solid with dimensions 7 mm × 2 mm × 2 mm.

The volume of one rice grain is

V = lwh = 7 mm × 2 mm × 2 mm = 28 mm³

Convert to cubic metres :

$V = \text{28 mm}^{3} \times \left (\dfrac{\text{1 m}}{\text{1000 mm}}\right )^{3} = \mathbf{2.8 \times 10^{-8}}\textbf{ m}^{\mathbf{3}}$

2. Volume of the room

V = lwh = 30.0 m × 8.5 m × 3.5 m = 890 m³

3. Volume of a mole of rice

$V= 6.022 \times 10^{23}\text{ grains} \times \dfrac{2.8 \times 10^{-8}\text{ m}^{3}}{\text{1 grain }} = \mathbf{1.7 \times 10^{16}}\textbf{ m}^{\mathbf{3}}$

4. Conclusion

The room is not big enough to hold a mole of rice.

If you work it out, you will find that it takes about

20 000 000 000 000 (twenty trillion) rooms to hold a mole of rice.

8 0

3 years ago

Calculate the standard cell potential of the following cell at 25°C. Sn(s) | Sn2+(aq) || Cu2+(aq) | Cu(s).

Semmy [17]

Answer:

0.48 V

Explanation:

Usually in the cell notation, the left side shows oxidation. So,

Oxidation half reaction:

$Sn_{(s)}\rightarrow Sn^{2+}_{(aq)}+2e^-$ $E^o_{ox}=-E^o_{red}=-(-0.14\ V)=0.14\ V$

Reduction half reaction:

$Cu^{2+}_{(aq)}+2e^-\rightarrow Cu_{(s)}$ $E^o_{red}=0.34\ V$

$E^o_{cell}=E^o_{ox}+E^o_{red}= (0.14+0.34)\ V=0.48\ V$

4 0

3 years ago

Calculate the average atomic mass of element X using the table below. Then use the periodic table to identify the element. Separ

Ksenya-84 [330]

Answer:

126.8, Iodine

Explanation:

mass ×abundance/100
(126.9045×80.45/100)+(126.0015×17.23/100)+(128.2230×2.23/100)
102.1+21.7+3=126.8

IODINE has an atomic mass of 126.8 or 126.9

4 0

3 years ago

Which element forms an ionic bond when combined with Cl

Shtirlitz [24]

Potassium or any other metals.

3 0

3 years ago

What causes metal to emit light?

Flauer [41]

Heating an atom excites its electrons and they jump to higher energy levels. When the electrons return to lower energy levels, they emit energy in the form of light. ... Every element has a different number of electrons and a different set of energy levels. Thus, each element emits its own set of colours.

5 0

3 years ago

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