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Zinaida [17]
3 years ago
10

The pile of ash left after a fire burns out demonstrates what concept? A. Original materials remain after a physical change. B.

A chemical change forms new substances. C. Physical properties are never stable. D. Fire recycles most substances.
Chemistry
1 answer:
Nana76 [90]3 years ago
5 0
The answer is A original materials remain after a physical.
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The three particles that make up atoms are
Anni [7]
A. Protons neutrons and electrons.

Haha those three make up a simple Atom.
6 0
3 years ago
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Nitrogen (N2) and hydrogen (H2) react to form ammonia (NH3). Consider a mixture of six nitrogen molecules and six hydrogen molec
Nezavi [6.7K]

Answer:

a)  No molecules of hydrogen

b) four molecules of ammonia

c) four left molecules of nitrogen.

Explanation:

The balanced reaction between nitrogen and hydrogen molecules to give ammonia molecules is:

N_{2}(g)+3H_{2}(g) -->2NH_{3}

Thus one molecule of nitrogen will react with three molecules of hydrogen to give two molecules of ammonia.

We have six molecules of each nitrogen and hydrogen in the closed container and they undergo complete reaction it means the limiting reagent is hydrogen. For six molecules of nitrogen, eighteen molecules of hydrogen will be required.

So six molecules of hydrogen will react with two molecules of nitrogen to give four molecules of ammonia.

The product mixture will have

a) No molecules of hydrogen

b) four molecules of ammonia

c) four left molecules of nitrogen.

7 0
3 years ago
#2: A gas at unknown pressure and a volume of 66 cm has its pressure changed to 150 kPa. The new volume
Murljashka [212]

Answer:

<h2>377 kPa</h2>

Explanation:

The original pressure can be found by using the formula for Boyle's law which is

P_1V_1 = P_2V_2

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

Since we're finding the original pressure

P_1 =  \frac{P_2V_2}{V_1}  \\

150 kPa = 150,000 Pa

We have

P_1 =  \frac{150000 \times 166}{66}  =  \frac{24900000}{66}  \\  = 377272.72...

We have the final answer as

<h3>377 kPa</h3>

Hope this helps you

7 0
3 years ago
What is the name of the compound that has the formula Li2SO3?
Oduvanchick [21]
The answer is A lithium sulfite
7 0
4 years ago
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A fossil was analyzed and determined to have a carbon-14 level that is 70 % that of living organisms. The half-life of C-14 is 5
Citrus2011 [14]

Answer: 2948

Explanation:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

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

k=\frac{0.69}{t_{\frac{1}{2}}}=\frac{0.693}{5730}=1.21\times 10^{-4}years^{-1}

Expression for rate law for first order kinetics is given by:

t=\frac{2.303}{k}\log\frac{a}{a-x}

where,

k = rate constant  = 1.21\times 10^{-4}years^{-1}

t = age of sample  = ?

a = let initial amount of the reactant  = 100

a - x = amount left after decay process = \frac{70}{100}\times 100=70

t=\frac{2.303}{1.21\times 10^{-4}}\log\frac{100}{70}

t=2948years

Thus the fossil is 2948 years old.

5 0
3 years ago
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