Can someone help me?

Distinguish between atom molecules, and ions

NNADVOKAT [17]

Explanation:

Atoms are the smallest unit of matter that can't be broken down chemically. Molecules are groups of two or more atoms that are chemically bonded. Ions are atoms or molecules that have gained or lost one or more of their valence electrons and therefore have a net positive or negative charge.

7 0

3 years ago

HELP PLEASE I HAVE A TEST TODAY AND I DON'T UNDERSTAND ANY OF THIS...

myrzilka [38]

Answer:

About 67 grams or 67.39 grams

Explanation:

First you would have to remember a few things:

enthalpy to melt ice is called enthalpy of fusion. this value is 6.02kJ/mol

of ice

it takes 4.18 joules to raise 1 gram of liquid water 1 degree C

water boils at 100 degrees C and water melts above 0 degrees C

1 kilojoules is 1000 joules

water's enthalpy of vaporization (steam) is 40.68 kJ/mol

a mole of water is 18.02 grams

we also have to assume the ice is at 0 degrees C

Step 1

Now start with your ice. The enthalpy of fusion for ice is calculated with this formula:

q = n x ΔH q= energy, n = moles of water, ΔH=enthalpy of fusion

Calculate how many moles of ice you have:

150g x (1 mol / 18.02 g) = 8.32 moles

Put that into the equation:

q = 8.32 mol x 6.02 = 50.09 kJ of energy to melt 150g of ice

Step 2

To raise 1 gram of water to the boiling point, it would take 4.18 joules times 100 (degrees C) or 418 joules.

So if it takes 418 joules for just 1 gram of water, it would take 150 times that amount to raise 150g to 100 degrees C. 418 x 150 = 62,700 joules or 62.7 kilojoules.

So far you have already used 50.09 kJ to melt the ice and another 62.7 kJ to bring the water to boiling. That's a total of 112.79 kJ.

Step 3

The final step is to see how much energy is left to vaporize the water.

Subtract the energy you used so far from what you were told you have.

265 kJ - 112.79 kJ = 152.21 kJ

Again q = mol x ΔH (vaporization)

You know you only have 152.21 kJ left so find out how many moles that will vaporize.

152.21 kJ = mol x 40.68 or mol = 152.21 / 40.68 = 3.74 moles

This tells you that you have vaporized 3.74 moles with the energy you have left.

Convert that back to grams.

3.74 mol x ( 18.02 g / 1 mol ) = 67.39 grams

5 0

2 years ago

Help mark brainliest !! Both dehydration and water addition to alkenes use h2so4 as a catalyst.Which is the difference between t

sasho [114]

Can u take a picture of it

7 0

3 years ago

How many significant figures does the number have? 9,000,100

Sergeeva-Olga [200]

Answer:

5 Significant Figures

Explanation:

6 0

3 years ago

A chemical reaction involves reactant species A, B, and C. Leaving all other factors identical, doubling the concentration of sp

umka21 [38]

Answer:

Rate = k . [B]² . [C]

Explanation:

The dependence of the reaction rate on the concentration of the reactants is given by the reaction order of each one, as shown in the rate equation.

$Rate=k.[A]^{x} .[B]^{y} .[C]^{z}$

where,

k is the rate constant

x, y, z are the reaction orders.

The rate of reaction is not affected by changing the concentration of species A. This means that the reaction order for A is x = 0 since when its concentration changes, the rate stays the same.

Leaving all other factors identical, doubling the concentration of species B increases the rate by a factor of 4. This means that the reaction order for B is y = 2, so when the concentration is doubled, the new rate is 2² = 4 times the initial rate.

The rate of the reaction is linearly dependent on the concentration of C. This means that the reaction order for C is z = 1, that is, a linear dependence.

All in all, the rate equation is:

Rate = k . [B]² . [C]

3 0

2 years ago