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2 years ago

Which one is a chemical reaction? Why?

Chemistry

1 answer:

Alex17521 [72]2 years ago

3 0

Answer:

Copper turns green on exposure to air

Explanation:

Liquid water freezes to form ice: Physical change

Reason: Water can melt back when it becomes ice.

Copper turns green on exposure to air: Chemical change

Reason: The copper can not change back from the green state when it turns green.

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Wastewater discharged into a stream by a sugar refinery contains 3.40 g of sucrose (C12H22O11) per liter. A government-industry

Ipatiy [6.2K]

Answer: The pressure that must be applied to the apparatus is 0.239 atm

Explanation:

To calculate the osmotic pressure, we use the equation for osmotic pressure, which is:

$\pi=iMRT$

or,

$\pi=i\times \frac{m_{solute}}{M_{solute}\times V_{solution}\text{ (in L)}}}\times RT$

where,

$\pi$ = osmotic pressure of the solution

i = Van't hoff factor = 1 (for non-electrolytes)

$m_{solute}$ = mass of sucrose = 3.40 g

$M_{solute}$ = molar mass of sucrose = 342.3 g/mol

$V_{solution}$ = Volume of solution = 1 L

R = Gas constant = $0.0821\text{ L atm }mol^{-1}K^{-1}$

T = temperature of the solution = $20^oC=[20+273]K=293K$

Putting values in above equation, we get:

$\pi =1\times \frac{3.40g}{342.3g/mol\times 1}\times 0.0821\text{ L. atm }mol^{-1}K^{-1}\times 293K\\\\\pi =0.239atm$

Hence, the pressure that must be applied to the apparatus is 0.239 atm

3 0

3 years ago

How does lanthanide contraction influence the density of period 6 transition element

Kitty [74]

Answer:

For example, the atomic radius of the metal zirconium, Zr, (a period-5 transition element) is 155 pm (empirical value) and that of hafnium, Hf, (the corresponding period-6 element) is 159 pm. ... The increase in mass and the unchanged radii lead to a steep increase in density from 6.51 to 13.35 g/cm3.

Explanation:

6 0

2 years ago

Someone help me pls will make you as brain

lesantik [10]

Answer:

i think so 1 and 3 is the correct answer...................

5 0

1 year ago

Read 2 more answers

2. ATO kg bouting ball would require what force to accelerate down an alleyway at a rate of ons?

Mars2501 [29]

Answer:

2. 30N

3. 5,000N

4. 15 kg

5. 2,800 kg

Explanation:

2. A 10 kg bowling ball would require what force to accelerate down an alleyway at a rate of 3m/s² ?

Notice that I completed the question with the garbled and missing values:

Data:

F = ?

m = 10 kg

a = 3m/s²

Physical principles:

Newton's second law: $F=m\times a$

Solution:

Substitute and compute

$F=10kg\times 3m/s^2=30N$

3. Salty has a car that accelerates at 5 m/s². If the car has a mass of 1000 kg, how much force does the car produce?

Notice that I arranged the typos.

Data:

F = ?

m = ?

a = ?

Physical principles:

Newton's second law: $F=m\times a$

Solution:

Substitute and compute

$F=1,000kg\times5m/s^2=5,000N$

4. What is the mass of a falling rock if it produces a force of 147 N?

Data:

F = 147N

m = ?

a = falling rock

Physical principles:

neglecting air resistance ⇒ a = g: gravitational acceleration: 9.8m/s²

Newton's second law: $F=m\times a$

Solution:

Clear m from Newton's second law

$m=\dfrac{F}{a}$

Substitute with F = 147 N and a = g = 9.8m/s², and compute

$m=\dfrac{147N}{9.8m/s^2}=15Kg$

5. What is the mass of a truck if it produces a force of 14,000 N while accelerating at a rate of 5 m/s²?

Data:

F= 14,000N

m = ?

a = 5m/s²

Physical principles:

Second Newton's law: $F=m\times a$

Solution:

Clear m from Newton's second law

$m=\dfrac{F}{a}$

Substitute with F = 14,000 N and a = 5m/s², and compute

$m=\dfrac{14,000N}{5m/s^2}=2,800kg$

6 0

2 years ago

There are several ways to model a compound. One type of model is shown.

yawa3891 [41]

Answer: The chemical formula for the formula given in the image is $C_4H_9O_2$ .

Explanation: There are many ways in which a model can be represented:

Molecular Formula
Ball and Stick formula
Expanded Formula
Condensed Formula
Skeletal Formula

This molecule is represented by the Expanded Structural Formula and by seeing in the image we can count the number of each element present.

Number of Carbon atoms present = 4

Number of Hydrogen atom present = 9

Number of Oxygen atom present = 2

Correct representation for this will be $C_4H_9O_2$ .

8 0

2 years ago

Read 2 more answers