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3 years ago

State 2 ways in which adaptation help animals?

1 answer:

6 0

Camouflage, mimicry, and animals' body parts and coverings are physical adaptations. The way in which an animal behaves is an adaptation, too—a behavioral adaptation . Behaviors that animals are born knowing how to do are instincts . A lion preying upon a zebra and a bird building a nest are examples of instincts.

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The following chemical equation is not balanced: I2 + Na2S2O3 NaI + Na2S4O6 When this chemical equation is correctly balanced, w

marshall27 [118]

Answer:

The answer is B

4 0

3 years ago

Calculate the enthalpy change, ∆H in kJ, for the reaction H2O(s) → H2(g) + 1/2O2(g). Use the following information: : +279.9 kJ

Len [333]

Answer:

+ 291.9 kJ

Solution:

The equation given is as;

H₂O ₍s₎ → H₂ ₍g₎ + 1/2 O₂ ₍g₎ ΔH = ?

First, as we know the heat of formation of H₂O ₍l₎ is,

H₂ ₍g₎ + 1/2 O₂ ₍g₎ → H₂O ₍l₎ ΔH = - 285.9 kJ

Now, reversing the equation will reverse the sign of heat as,

H₂O ₍l₎ → H₂ ₍g₎ + 1/2 O₂ ₍g₎ ΔH = + 285.9 kJ

Also, we know that,

H₂O ₍s₎ → H₂O ₍l) ΔH = + 6.0 kJ

Now, adding last two equations,

H₂O ₍l₎ → H₂ ₍g₎ + 1/2 O₂ ₍g₎ ΔH = + 285.9 kJ

H₂O ₍s₎ → H₂O ₍l) ΔH = + 6.0 kJ

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

H₂O ₍s₎ → H₂ ₍g₎ + 1/2 O₂ ₍g₎ ΔH = + 291.9 kJ

5 0

3 years ago

Which reactions are single displacement reactions? 2NaBr + CaF2 → 2NaF + CaBr2 SnO2 + 2H2 → Sn + 2H2O 4Na + O2 → 2Na2O 2KClO3 →

r-ruslan [8.4K]

Answer : The correct options are, $SnO_2+2H_2\rightarrow Sn+2H_2O$ and $2Al+6HCl\rightarrow 2AlCl_3+3H_2$

Explanation :

Single displacement reaction : It is a type of chemical reaction in which the more reactive element displaces the less reactive element.

Option A reaction : $2NaBr+CaF_2\rightarrow 2NaF+CaBr_2$

It is an example of double displacement reaction because in this reaction a positive cation and a negative anion of the two reactants exchange their places to form two new products.

Option B reaction : $SnO_2+2H_2\rightarrow Sn+2H_2O$

It is an example of single displacement reaction.

Option C reaction : $4Na+O_2\rightarrow 2Na_2O$

It is an example of combination reaction because in this reaction two reactants react to give a single product.

Option D reaction : $2KClO_3\rightarrow 2KCl+3O_2$

It is an example of decomposition reaction because in this reaction a single reactant decomposes into two or more products.

Option E reaction : $2Al+6HCl\rightarrow 2AlCl_3+3H_2$

It is an example of single displacement reaction because in this reaction the most react element, aluminium displaces the less reactive element, hydrogen.

Hence, the options B and E are single displacement reactions.

5 0

3 years ago

A non-stoichiometric compound is a compound that cannot be represented by a small whole-number ratio of atoms, usually because o

ikadub [295]

<span>Average oxidation state = VO1.19
Oxygen is-2. Then 1.19 (-2) = -2.38
Average oxidation state of V is +2.38

Consider 100 formula units of VO1.19
There would be 119 Oxide ions = Each oxide is -2. Total charge = -2(119) = -238
The total charge of all the vanadium ions would be +238.
Let x = number of of V+2
Then 100 – x = number of V+3
X(+2) + 100-x(+3) = +238
2x + 300 – 3x = 238
-x = 238-300 = -62
x = 62

Thus 62/100 are V+2
62/100 * 100 = 62%

</span>62 % is the percentage of the vanadium atoms are in the lower oxidation state. Thank you for posting your question. I hope that this answer helped you. Let me know if you need more help.

7 0

3 years ago

How to separate sand from salt

IRINA_888 [86]

Put the salt and sand in some water.
the salt will not be visible but the sand will
now strain the the sand from the water
now boil the water and now the water will boil away and now you will just have salt left.

6 0

3 years ago