I need help!!!!!!!!!!!!!!!!!!!!!!!!!!!

1. There are how many mol of oxygen in 3.5 mol of caffeine.

inysia [295]

Answer:

7 mol

Explanation:

Caffeine molecular formula C8H10N4O2. It has 2 atoms of oxygen.

C8H10N4O2 - 2O

1 mol 2 mol

3.5 mol x mol

x = 3.5*2/1 = 7 mol

3 0

3 years ago

The same heat transfer into identical masses of different substances produces different temperature changes. Calculate the final

myrzilka [38]

Answer: final temperatures will be

a) water 21 C

b) concrete 20.005 C

c) steel 20.008 C

d) mercury 53 C

Explanation:

Change in temp dT = dH / (mass x specific heat)

Specific heat of these materials can be found from many sources:

water = 1 kcal / kg C

concrete = 210 kcal / kg C

steel = 114 kcal / kg C

mercury = 0.03 kcal /kg C

So dT (water) from 1 kcal heat into 1 kg water = 1 kcal / (1 kg x 1 kcal/kg C) = 1 C therefore the final temperature is 20 + 1 = 21 C

But dT (steel) = 1 kcal / (1kg x 114 kcal/kg C) = 0.008 C so the final temperature is 20 + 0.008 = 20.008 C

The results for concrete and mercury are calculated in the same way

7 0

3 years ago

What does the reaction rate say about a reaction?

miss Akunina [59]

Answer:

It shows the change in concentration of a reactant or product per unit of time, expressed as mol/(L · s)

Explanation:

The reaction rate is the speed at which a chemical reaction proceeds.

So if the reaction rate is the speed at which a chemical reaction happens/occurs, then the reaction rate will tell us about the concertation of the chemicals. It shows the change in concentration of a reactant or product per unit of time, expressed as mol/(L · s)

7 0

3 years ago

The primary goal of water-softening ion exchange systems is _____(1 point)

Anettt [7]

Answer:

The primary goal of water-softening ion exchange systems is _____(1 point)

removing magnesium and calcium from water. ***

removing sodium from water.

introducing magnesium and calcium into water.

introducing sodium into water.

How does a reverse osmosis water purification system operate? (1 point)

Untreated water is subjected to high pressure, causing it to move through a highly permeable membrane, which captures contaminants.

Untreated water is subjected to high pressure, causing it to move through a semi-permeable membrane, which captures contaminants. ***

Untreated water is subjected to low pressure, causing it to move through a highly permeable membrane, which captures contaminants.

Untreated water is subjected to low pressure, causing it to move through a semi-permeable membrane, which captures contaminants.

A city council is debating between two potential water purification systems: reverse osmosis and ion exchange. Cost is the primary criteria for the choice. Which decision is the most likely result of this debate?(1 point)

More research is needed because reverse osmosis systems require specialized maintenance, while ion exchange requires regular replacement of components. ***

A reverse osmosis system would likely be chosen because it does not require specialized maintenance or regular replacement of components.

More research is needed because ion exchange systems require specialized maintenance, while reverse osmosis requires regular replacement of components.hdhdhd

An ion exchange system would likely be chosen because it does not require specialized maintenance or regular replacement of components.

A city council is debating different alternatives for purifying water from a local reservoir. The council is considering ion exchange and reverse osmosis. Bacterial contamination of the water supply is the primary concern, and the council has decided that dealing with this is the main criteria for their choice. Which decision is the most likely outcome of this debate?(1 point)

They are likely to choose reverse osmosis because it is specifically designed to kill bacteria.

They are likely to choose ion exchange because it is specifically designed to kill bacteria.

They are likely to choose reverse osmosis because it addresses a wider range of problems, including bacteria. ***

They are likely to choose ion exchange because it addresses a wider range of problems, including bacteria.

Which of the following is a constraint of a chlorine bleach shock to remove contaminants from drinking water?(1 point)

This treatment only removes large solids.

This treatment only removes microscopic contaminants.

This treatment does not remove bacteria.

This treatment removes bacteria, but not other pollutants. ***

5 0

3 years ago

Name the following alkyne.<br> Please help me <3

Alexandra [31]

Answer:

D. 7-methyl-3-octyne

Explanation:

1) Identify the parent chain and name it like an alkane.

• The longest chain of carbons, which consists of the functional group (which is the alkyne group in this case: C≡C).

• There are 8 carbons in the longest chain, so it is called an octane.

2) Now, identify the location of the functional group.

• The location number of the functional group should be as low as possible. Thus although we could count from the right, we start counting from the left since the functional group is closer to the left. From the left, the functional group would be at carbon 8 while from the left, it is on carbon 3.

• Replace 'ane' with 'yne' in octane for the alkyne group.

• This would give us 3-octyne.

3) Lastly, add in the name of the branch.

• Here we have one branch, -CH₃. This is read as methyl.

• Identify the location number of the branch by counting the number of carbons in the same direction as when we counted the location number of the functional group. The methyl branch has a location number of 7.

• Adding the name of the branch before the parent chain, we would arrive at 7-methyl-3-octyne as the IUPAC name of the alkyne.

Further Explanation:

A) This option is incorrect as there are only 8 carbons in the parent chain. Although there are 9 carbons in total, the 9th carbon is taken care of in '7-methyl'.

B) Location number of the functional group should be as low as possible, so start counting the number of carbons from the left!

C) Since the functional group is an alkyne, the word 'octane' should be 'octyne' instead.

8 0

3 years ago