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3 years ago

11

If white light shines on an object and the red, orange, green, blue, indigo, and violet light is absorbed. What color does your

eye see? (hint: see what color is missing)
Question options:

Purple

White

Red

Yellow

2 answers:

bazaltina [42]3 years ago

7 0

Yellow is the answer hope this helps

Sedaia [141]3 years ago

6 0

Hello
it would be yellow dats missing

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Which organisms are consumers?

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Answer: snake grass hopper and monkey

Explanation: i took the test and this is what i got

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2 years ago

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Read that From picture and tell me the answer please

Dafna11 [192]

Answer:

1g Hydrogen

Explanation:

<h3><u>Getting</u><u> </u><u>to</u><u> </u><u>the</u><u> </u><u>equation</u><u>:</u></h3>

Calcium in water reacts vigorously to give a cloudy white <em>Precipitate</em><em> </em>(compound) called Calcium hydroxide alongwith the evolution of Hydrogen gas.

$\boxed{ \mathsf{Ca + H_2O \rightarrow Ca(OH)_2 + H_2}}$

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

<h3><u>Balancing</u><u> </u><u>the</u><u> </u><u>equation</u><u>:</u><u> </u></h3>

This reaction is not in it's balanced form! The number of atoms of Hydrogen on the left is 2 while that on the right is 4,I.e.,they're not equal.

Adding a 2 in front of H2O solves the problem by making the number of atoms of each element on both the sides equal.

$\mathsf{Ca +2 H_2O \rightarrow Ca(OH)_2 + H_2}$

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

<h3><u>Observations</u><u>:</u></h3>

Looking into the equation more carefully, we see:

<u><em>1</em><em> </em></u><em>atom</em><em> </em><em>of</em><em> </em><em>Calcium</em><em> </em><em>reacts</em><em> </em><em>with</em><em> </em><em><u>2</u></em><em> </em><em>molecules</em><em> </em><em>of</em><em> </em><em>water</em><em> </em><em>to</em><em> </em><em>give</em><em> </em><u><em>1</em><em> </em></u><em>molecule</em><em> </em><em>of</em><em> </em><em>Calcium</em><em> </em><em>Hydroxide</em><em> </em><em>alongwith</em><em> </em><em><u>1</u></em><em> </em><em>molecule</em><em> </em><em>of</em><em> </em><em>Hydrogen</em><em> </em><em>gas</em><em>.</em>

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

<h3><u>Gram</u><u> </u><u>atomic</u><u> </u><u>and</u><u> </u><u>molecular</u><u> </u><u>masses</u><u> </u></h3>

<u>Mass</u><u> </u><u>of</u><u> </u><u>one</u><u> </u><u>atom</u><u> </u><u>of</u><u> </u><u>Calcium</u><u> </u>= it's gram atomic mass

= 40 g

<u>Mass of one "molecule" of Hydrogen</u>

= it's Gram molecular mass

= gram mass of one atom × number of atoms in one molecule

= 1 × 2

= 2 g

So,

according to our observation:

One atoms of Calcium gives one molecule of Hydrogen <em>(during the particular reaction)</em>

=><u> 40g of Calcium gives = 2g of Hydrogen</u>

•°• 1 g of Calcium gives = $\frac{2}{40}$

= $\frac{1}{20}$ g Hydrogen

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

<h3><u>Answer</u><u>:</u></h3>

We're provided with 20g of Calcium,

=> 20g of Calcium gives = 20 × $\frac{1}{20}$ g H2

<u>= 1 g H2</u>

_______________

Hope this helps!

6 0

2 years ago

The activation energy for a reaction is changed from 184 kJ/mol to 60.5 kJ/mol at 600. K by the introduction of a catalyst. If t

Ahat [919]

Answer:

The catalyzed reaction will take 1,41 s

Explanation:

The rate constant for a reaction is:

$k = A e^{-\frac{Ea}{RT}}$

Assuming frequency factor is the same for both reactions (with and without catalyst) it is possible to obtain:

${\frac{k1}{k2}} = e^{-\frac{Ea_{2}-Ea_{1}}{RT}}$

Replacing:

${\frac{k1}{k2}} = e^{-\frac{60,5kJ/mol-184kJ/mol}{8,314472x10^{-3}kJ/molK*600k}}$

${\frac{k1}{k2}} = 5,64x10^{10}$

That means the reaction occurs 5,64x10¹⁰ faster than the uncatalyzed reaction, that is 2537 years / 5,64x10¹⁰ = 4,50x10⁻⁸ years. In seconds:

4,50x10⁻⁸ years× $\frac{365days}{1year}$ × $\frac{24hours}{1day}$ × $\frac{3600s}{1hour}$ =<em> 1,41 s</em>

I hope it helps!

6 0

3 years ago

When 2.16g of H2 reacts with excess O2 by the following equation, 258 kJ of heat are released. What is the change of enthalpy as

alekssr [168]

Answer:

-241 kJ/mol

Explanation:

Let's consider the reaction of hydrogen with excess oxygen to form water.

2 H₂ + O₂ ⟶ 2 H₂O

When 2.16g of hydrogen reacts with excess oxygen, 258 kJ of heat are released, that is, Q = -258 kJ. Considering that the molar mass of hydrogen is 2.02 g/mol, the change of enthalpy associated with the reaction of 1.00 mol of hydrogen gas is:

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3 years ago

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marin [14]

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</span>

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3 years ago