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3 years ago

13

Which statement describes the general trends in electronegativity and metallic properties as the elements in Period 2 are consid

ered in order of increasing atomic number?

1 answer:

zysi [14]3 years ago

3 0

Answer:

Electronegativity increases and metallic

properties decrease.

Explanation:

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Scientists test their ideas about things they cannot observe directly by building

Karo-lina-s [1.5K]

Answer:

yes

Explanation:

Testing scientific ideas

Testing Ideas. Testing hypotheses and theories is at the core of the process of science. ... match actual results observation, that lends support.

5 0

3 years ago

what is the mass of water vapor produced when 3.2 liters reacts with 8.7 liters of oxygen gas at STP?

uranmaximum [27]

Answer:

2.57g

Explanation:

First, let us write a balanced equation for the reaction. This is illustrated below:

2H2 + O2 —> 2H2O

Next let us determine the limiting reactant. This is achieved as follows:

From the equation,

2L H2 required 1L of O2.

Therefore, 3.2L of H will require = 3.2/2 = 1.6L of O2

From the calculation above, O2 is excess because the volume of O2 given from the question is far greater than the volume of O2 obtained from our calculation. Therefore, H2 is the limiting reactant.

Now let us covert 3.2L of H2 to mole. This is illustrated below:

1mole of a gas occupy 22.4L at stp

Therefore, Xmol of H2 will occupy 3.2L i.e

Xmol of H2 = 3.2/22.4 = 0.143mol

From the equation,

2moles of H2 produced 2moles of H2O.

Therefore, 0.143mol of H2 will also produce 0.143moles of H2O.

Now, we can obtain the mass of the water vapour produced by convert 0.143mol of H2O to gram. This is illustrated below:

Molar Mass of H2O = (2x1) + 16 = 2 + 16 = 18g/mol

Number of mole of H2O = 0.143mol

Mass of H2O =?

Mass = mole x Molar Mass

Mass of H2O = 0.143 x 18 = 2.57g

The mass of water vapour produce is 2.57g

8 0

3 years ago

g On the basis of their respective pKa values, determine which is the stronger acid, acetic acid (pKa 5 4.7) or benzoic acid (ma

ozzi

Answer:

Benzoic acid is the stronger acid

Explanation:

Weak acids do not dissociate completely in the solution. They exists in equilibrium with their respective ions in the solution.

The extent of dissociation of the acid furnising hydrogen ions can be determined by using dissociation constant of acid ( $K_a$ ).

Thus for a weak acid, HA

$HA \rightleftharpoons A^- + H^+$

The $K_a$ is:

$K_a= \frac{[A^-][H^+]}{[HA]}$

The more the $K_a$ , the more the acid dissociates, the more the stronger is the acid.

Also,

$pK_a$ is defined as the negative logarithm of $K_a$ .

So, more the $pK_a$ , less is the $K_a$ and vice versa

All can be summed up as:

The less the value of $pK_a$ , the more the $K_a$ is and the more the acid dissociates and the more the stronger is the acid.

Given,

$pK_a$ of acetic acid = 54.7

$pK_a$ of benzoic acid = 54.2

$pK_a$ of benzoic acid < $pK_a$ of acetic acid

So, benzoic acid is the stronger acid.

5 0

4 years ago

A 50.00 g sample of an unknown metal is heated to 45.00°C. It is then placed in a coffee-cup calorimeter filled with water. The

True [87]

First, in order to calculate the specific heat capacity of the metal in help in identifying it, we must find the heat absorbed by the calorimeter using:
Energy = mass * specific heat capacity * change in temperature
Q = 250 * 1.035 * (11.08 - 10)
Q = 279.45 cal/g

Next, we use the same formula for the metal as the heat absorbed by the calorimeter is equal to the heal released by the metal.

-279.45 = 50 * c * (11.08 - 45) [minus sign added as energy released]
c = 0.165

The specific heat capacity of the metal is 0.165 cal/gC

6 0

3 years ago

Read 2 more answers

Can u help me pls.

lakkis [162]

Answer:

its g :)

Explanation:

8 0

3 years ago