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2 years ago

Why do we need an isolated system for the law of conservation of mass to be true?

2 answers:

8 0

The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.

Alex_Xolod [135]2 years ago

7 0

Answer:

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Consider the first-order reaction described by the equation At a certain temperature, the rate constant for this reaction is 5.8

zubka84 [21]

<u>Answer:</u> The half life of the reaction is 1190.7 seconds

<u>Explanation:</u>

The equation used to calculate rate constant from given half life for first order kinetics:

$t_{1/2}=\frac{0.693}{k}$

where,

k = rate constant of the reaction = $5.82\times 10^{-4}s^{-1}$

$t_{1/2}$ = half life of the reaction = ?

Putting values in above equation, we get:

$t_{1/2}=\frac{0.693}{5.82\times 10^{-4}s^{-1}}=1190.7s$

Hence, the half life of the reaction is 1190.7 seconds

8 0

2 years ago

Tisa makes a diagram to organize her notes about charging objects.

Amanda [17]

The answer is Electrons move between objects. The reason this is known is that the acts of friction and conduction (from the little picture he could not put in) involves contact to be known as friction and conduction. Without contact the electrons could not move between objects. I also got this question right on the test. That's how I know this is right. I hope this helps. ( ͡° ͜ʖ ͡°)

8 0

2 years ago

Read 2 more answers

If 100 ml of a 0.5 M HCI Solution is diluted with water to 1000ml, what is the new concetration?

Vesna [10]

Answer:

$0.05\ \text{M HCl}$

Explanation:

$V_1$ = Initial volume = 100 mL

$V_2$ = Final volume = 1000 mL

$M_1$ = Initial concentration = 0.5 M

$M_2$ = Final concentration

We have the relation

$\dfrac{M_1}{M_2}=\dfrac{V_2}{V_1}\\\Rightarrow M_2=M_1\dfrac{V_1}{V_2}\\\Rightarrow M_2=0.5\times \dfrac{100}{1000}\\\Rightarrow M_2=0.05\ \text{M HCl}$

The new concentration is $0.05\ \text{M HCl}$ .

3 0

2 years ago

How did thompson know the charge of the particle he discovered was negative?

bulgar [2K]

Answer:

Explanation:

The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.

Symbol= e-

Mass= 9.10938356×10-31 Kg

It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.

He constructed the glass tube and create vacuum in it. He applied electric current between electrodes. He noticed that a ray of particles coming from cathode to wards positively charged anode. This ray was cathode ray.

Properties of cathode ray:

The ray is travel in straight line.

The cathode ray is independent of composition of cathode.

When electric field is applied cathode ray is deflected towards the positively charged plate.

Hence it was consist of negatively charged particles.

8 0

2 years ago

Look at this balanced chemical reaction: N2 + 3H2 2NH3

stepladder [879]

Answer: A mass of 124457.96 g ammonia is produced by reacting a 450 L sample of nitrogen gas at a temperature of 450 K and a pressure of 300 atm.

Explanation:

Given: Volume = 450 L

Temperature = 450 K

Pressure = 300 atm

Using ideal gas equation, moles of nitrogen are calculated as follows.

PV = nRT

where,

P = pressure

V = volume

n = no. of moles

R = gas constant = 0.0821 L atm/mol K

T = tempertaure

Substitute values into the above formula as follows.

$PV = nRT\\300 atm \times 450 L = n \times 0.0821 L atm/mol K \times 450 K\\n = \frac{135000}{36.945}\\= 3654.08 mol$

According to the given equation, 1 mole of nitrogen forms 2 moles of ammonia. So, moles of ammonia formed by 3654.08 moles of nitrogen is as follows.

$2 \times 3654.08 mol\\= 7308.16 mol$

As moles is the mass of substance divided by its molar mass. So, mass of ammonia (molar mass = 17.03 g/mol) is as follows.

$Moles = \frac{mass}{molar mass}\\7308.16 = \frac{mass}{17.03 g/mol}\\mass = 124457.96 g$

Thus, we can conclude that a mass of 124457.96 g ammonia is produced by reacting a 450 L sample of nitrogen gas at a temperature of 450 K and a pressure of 300 atm.

8 0

2 years ago