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3 years ago

What is energy= energy out

2 answers:

5 0

Total energy put into the system, a closed system must equal the total energy coming off or exiting the system, in other words, total energy is and must be conserved. The difference then would be zero, as energy in = energy out.

zubka84 [21]3 years ago

4 0

I think it might mean like energy went off not sure tho

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Is copper sulphate malleable?

jonny [76]

Answer:

Yes, Copper (Cu) in its pure form is a reddish-brown metallic element with high ductility and malleability that is an excellent conductor of heat and electricity: atomic weight 63.54; atomic number 29; density 8.94 g/cm3; melting point 1083°C; and boiling point 2595°C.

8 0

3 years ago

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A cylinder with a radius of 5.6 cm and a height of 10.7 cm has what volume? (You can look up the formula for the volume of a cyl

Keith_Richards [23]

Answer:

$V=1054.2cm^{3}$

Explanation:

1. First take the cylinder volume formula:

$V=\pi.r^{2}.h$

2. Then take the values for the radius and the height of the cylinder and replace them into the formula:

$V=\pi*(5.6cm)^{2}*(10.7cm)$

3. Solve the equation:

$V=\pi*(31.36cm^{2})*(10.7cm)$

$V=\pi*335.5cm^{3}$

$V=1054.2cm^{3}$

6 0

3 years ago

Give 3 example<br>of a<br>solid that sublimes.

tino4ka555 [31]

Here are a few examples :)

iodine (I2)

naphthalene

aresenic (As)

ferrocene

water (H2O)

carbon dioxide (CO2)

Hope this helps :)

5 0

3 years ago

50.00 mL of 0.10 M HNO 2 (nitrous acid, K a = 4.5 × 10 −4) is titrated with a 0.10 M KOH solution. After 25.00 mL of the KOH sol

boyakko [2]

Answer:

b. 3.35

Explanation:

To calculate the pH of a solution containing both acid and its salt (produced as a result of titration) we need to use Henderson’s equation i.e.

pH = pKa + log ([salt]/[acid]) (Eq. 01)

Where

pKa = -log(Ka) (Eq. 02)

[salt] = Molar concentration of salt produced as a result of titration

[acid] = Molar concentration of acid left in the solution after titration

Let’s now calculate the molar concentration of HNO2 and KOH considering following chemical reaction:

HNO2 + KOH ⇆ H2O + KNO2 (Eq. 03)

This shows that 01 mole of HNO2 and 01 mole of KOH are required to produce 01 mole of KNO2 (salt). And if any one of them (HNO2 and KOH) is present in lower amount then that will be considered the limiting reactant and amount of salt produced will be in accordance to that reactant.

Moles of HNO2 in 50 mL of 0.01 M HNO2 solution = 50/1000x0.01 = 0.005 Moles

Moles of KOH in 25 mL of 0.01 M KOH solution = 25/1000x0.01 = 0.0025 Moles

As it can be seen that we have 0.0025 Moles of KOH therefore considering Eq. 03 we can see that 0.0025 Moles of KOH will react with only 0.0025 Moles of HNO2 and will produce 0.0025 Moles of KNO2.

Therefore

Amount of salt produced i.e [salt] = 0.0025 moles (Eq. 04)

Amount of acid left in the solution [acid] = 0.005 - 0.0025 = 0.0025 moles (Eq.05)

Putting the values in (Eq. 01) from (Eq.02), (Eq. 04) and (Eq. 05) we will get the following expression:

pH= -log(4.5x10 -4) + log (0.0025/0.0025)

Solving above we get

pH = 3.35

5 0

3 years ago

Study the graph about oxygen content of Earth’s atmosphere. Oxygen Content of Earth apostrophe s Atmosphere line graph. X axis i

Anika [276]

Explanation:

from the graph study about oxygen content of Earth's atmosphere, we can understand that

4 billions year ago = None, 3 billions year ago = Cyanobacteria and Archaea , 2 and 1 billions year ago = Bacteria and Green algae , 500 Ma = invertebrate fossils started to existence. Early land plants came in to existence around 398 MA that is Devonian. Dinosaurs are came in to existence during Triassic and Jurassic that is around 251 Ma. Man and animals are recent organism came under Holocene that is 11000 years ago.

The first cells on the earth are anaerobic microorganisms, as the CO2 level is too high they survive by using CO2.

Starting around 2.7 billion years ago, photosynthesis by Cyanobacteria and later plants , pumped “OXYGEN” in to the atmosphere. This caused the decline of anaerobic bacteria and allows the diversification of animals as seen in “CAMBRIAN” around 500 millions year ago.

Early vascular plants “CAPTURED” CO2 starting before the Carboniferous period that began around 350 millions year.Leading to lower temperatures and allowing and allowing the seed plants to outcompetes seedless plants.

Modern human activities has raised both “CO2 and METHANE” level in the atmosphere to over leading to higher temperature and extinction of other species.

3 0

3 years ago

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