If the element is closer to the top of the table is it's ionization energy larger?

Which is an example of an endothermic reaction? A. combustion of fuels B. burning of wood C. cellular respiration D. photosynthe

kifflom [539]

D. photosynthesis is an endothermic reaction

8 0

3 years ago

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Ethanol has a density of 0.789 g/cm3. What is the mass of 423 cm3 of ethanol? M = (D)(V)

Ivahew [28]

Answer:

<h2>The answer is 334 g</h2>

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

<h3>mass = Density × volume</h3>

From the question

volume of ethanol = 423 cm³

density = 0.789 g/cm³

So we have

mass = 0.789 × 423 = 333.747

We have the final answer as

Hope this helps you

6 0

3 years ago

A graduated cylinder was filled with 25.0 mL of water. A solid object was immersed in the cylinder, raising the water level to 3

yawa3891 [41]

Answer:

Density of the object is 8759.494 grams/L

Explanation:

As we know density of an object is mass of the object divided by its volume

Given

Volume of the object is equal to the change in volume of water with in the cylinder when the object was immersed in water.

Hence, volume of object is equal to

$32.9 -25 = 7.9$ mL

Mass of the object is $69.2$ grams

Density

$= \frac{69.2}{7.9 *10^{-3}}\\= 8759.494$ grams/L

Density of the object is 8759.494 grams/L

7 0

3 years ago

When the pH of a solution changes from a pH of 5 to a pH of 3, the hydronium ion concentration is

gizmo_the_mogwai [7]

Answer : The correct option is, (D) 100 times the original content.

Explanation :

As we are given the pH of the solution change. Now we have to calculate the ratio of the hydronium ion concentration at pH = 5 and pH = 3

As we know that,

$pH=-\log [H_3O^+]$

The hydronium ion concentration at pH = 5.

$5=-\log [H_3O^+]$

$[H_3O^+]=1\times 10^{-5}M$ ..............(1)

The hydronium ion concentration at pH = 3.

$3=-\log [H_3O^+]$

$[H_3O^+]=1\times 10^{-3}M$ ................(2)

By dividing the equation 1 and 2 we get the ratio of the hydronium ion concentration.

$\frac{[H_3O^+]_{original}}{[H_3O^+]_{final}}=\frac{1\times 10^{-5}}{1\times 10^{-3}}=\frac{1}{100}$

$100\times [H_3O^+]_{original}=[H_3O^+]_{final}$

From this we conclude that when the pH of a solution changes from a pH of 5 to a pH of 3, the hydronium ion concentration is 100 times the original content.

Hence, the correct option is, (D) 100 times the original content.

7 0

3 years ago

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Mass does not change during a chemical change. is the same true for physical change?

Mashutka [201]

Answer:

Mass states that mass is neither created nor destroyed in a chemical reaction or a physical transformation

Explanation:

4 0

3 years ago