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dezoksy [38]
2 years ago
8

For which of the following activities might you want to hire a chemist?

Chemistry
2 answers:
worty [1.4K]2 years ago
7 0

For which of the following activities might you want to hire a chemist?

Answer: D. testing a rock sample for gold content

Which of the following procedures involves a physical change in one of the substances?

Answer: C. separating a salt solution by evaporating the water

Crank2 years ago
6 0

A. examining the structure of plant cells  

Incorrect. A biologist is required.  

B. building a fence

Incorrect. A carpenter is required.  

C. building a wood storage shed

Incorrect. A carpenter is required.  

D. testing a rock sample for gold content

Incorrect. A chemist is required.  

A. creating salt by reacting sodium metal and chlorine gas

Incorrect. This is a chemical change as a new product is formed.  

B. allowing a nail rust

Incorrect. This is a chemical change as it is the oxidation of iron to form iron oxide, rust.  

C. separating a salt solution by evaporating the water

Correct. This is a physical change as salt gets separated from water and no new product is formed.  

D. building a model rocket propelled by mixing baking soda and vinegar

Incorrect. This is a chemical change.  

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After each step in a dichotomous key, the questions get ________.
GenaCL600 [577]

Answer:

I believe the answer is 1. more specific.

Explanation:

Since the dichotomous key is used to identify a species, you would have to get down to the specifics, so specificity is required.

4 0
2 years ago
Read 2 more answers
PLEASE HELP !
mario62 [17]

Answer:

2L of water.

Explanation:

To know the volume of water to be added to the initial solution, first let us calculate the volume of the final solution. This is illustrated below:

Data obtained from the question:

Initial volume (V1) = 2L

Initial concentration (C1) = 6mol/L

Final concentration (C2) = 3mol/L

Final volume (V2) =?

Using the dilution formula, we can obtain the final volume of the stock as follow:

C1V1 =C2V2

6 x 2 = 3 x V2

Divide both side by 3

V2 = (6 x 2)/3

V2 = 4L.

The final volume of the solution is 4L.

To obtain the volume of water added, we shall determine the change in the volume of the solution. This is illustrated below:

Initial volume (V1) = 2L

Final volume (V2) = 4L

Change in volume = V2 – V1 = 4 – 2 = 2L.

Therefore, 2L of water must be added to the initial solution.

4 0
3 years ago
2Ag + H2S ➞ Ag2S + H2
NeX [460]

Answer:

The correct answer is <em>C)  Two atoms of silver are needed to complete the reaction.</em>

Explanation:

The Law of Conservation of Matter postulates that "the mass is not created or destroyed, only transformed." This means that the reagents interact with each other and form new products with physical and chemical properties different from those of the reagents because the atoms of the substances are ordered differently. But the amount of matter or mass before and after a transformation (chemical reaction) is always the same, that is, the quantities of the masses involved in a given reaction must be constant at all times, not changing in their proportions when the reaction ends.

Then, taking into account the Law of Conservation of Matter, as an atom cannot be created or destroyed in a chemical reaction, the number of atoms that are present in the reagents has to be equal to the number of atoms present in the products.

For this, the chemical equation must be balanced. For that, you must first look at the subscripts next to each atom to find the number of atoms in each compound in the equation. If the same atom appears in more than one molecule, you must add its quantities. On the other hand, the coefficients located in front of each molecule indicate the amount of each molecule for the reaction. This coefficient can be modified to balance the equation, just as you should never alter the subscripts. By multiplying the coefficient mentioned by the subscript, you get the amount of each element present in the reaction.

In this case:

Left side: 2 silver  (Ag), 2 hydrogen (H) and 1 sulfur (S)

Right side: 2 silver  (Ag), 2 hydrogen (H) and 1 sulfur (S)

In this case the equation is balanced because you have the same amount of all the elements on each side of the reaction. And <u><em>the 2 in front of 2Ag indicates that,since silver is a reagent, two atoms of silver are needed to complete the reaction. (option C).</em></u>

4 0
3 years ago
Read 2 more answers
In H2O, the 2 is called a
GaryK [48]
2 hydrogen atoms hope this helps
6 0
3 years ago
How many grams of water will be produced when 1.6 moles of ethanol (CH3CH2OH) are burned completely? Enter a number only (no uni
AfilCa [17]

Answer:

86

Explanation:

The reaction that takes place is:

  • C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O

First we <u>convert moles of ethanol to moles of water</u>:

  • 1.6 mol ethanol * \frac{3molH_2O}{1molEthanol} = 4.8 mol H₂O

Then we <u>convert moles of water to grams of water</u>, using its molar mass:

  • 4.8 mol H₂O * 18 g/mol = 86.4 g

So 84.6 grams of water will be produced.

4 0
2 years ago
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