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dezoksy [38]
3 years ago
8

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

Chemistry
2 answers:
worty [1.4K]3 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

Crank3 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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A) How much energy would be required to melt 500 grams of ice at 0°C to water at 0°C?
baherus [9]

Heat required = Q = 40 kcal

<h3>Further explanation</h3>

Given

mass of 500 g ice

Required

Heat required

Solution

The heat to change the phase can be formulated :  

  • Q = m.Lf (melting/freezing)  
  • Q = m.Lv (vaporization/condensation)  

Lf=latent heat of fusion  

Lv=latent heat of vaporization  

Lf for water = 334 kj/kg=6.01 kJ/mol = 80 cal/g

Phase change(ice to water)

Q=  500 g x 80 cal/g

Q = 40 kcal

4 0
3 years ago
Is usually categorized to a specific area in the state known as a soil series
Vikentia [17]

Answer:

Soil series as established by the National Cooperative Soil Survey of the United States Department of Agriculture (USDA) Natural Resources Conservation Service are a level of classification in the USDA Soil Taxonomy classification system hierarchy. The actual object of classification is the so-called soil individual, or pedon.[1] Soil series consist of pedons that are grouped together because of their similar pedogenesis, soil chemistry, and physical properties. More specifically, each series consists of pedons having soil horizons that are similar in soil color, soil texture, soil structure, soil pH, consistence, mineral and chemical composition, and arrangement in the soil profile.[2] These result in soils which perform similarly for land use purposes.

Explanation:

hope its correct

6 0
3 years ago
Lab Report
Alenkasestr [34]

Answer:

I know some of them...

Explanation:

1. What was the purpose of the experiment?

Type your answer here: The purpose of this experiment is to show that a cell membrane is a type of barrier, and is permeable to some substances, but may not be permeable to all substances.

2. What were the independent, dependent, and control variables in your investigation? Describe the variables used in the part of the experiment with the eggs.

Type your answer here: Independent variable / Manipulated variable: Refers to all the variables in an experiment that provoke a response in another variable. This variable is modified during the experiment to analyze how another variable responds to it. The researcher wants to study how the changes in these variables affect the dependent variable.  The researcher can change these variables to see what changes it implies in an object, process, trait, or anything that depends on them.

Dependent variable / Responding variable: Its response depends on any change in the independent variable. The dependent variable is the one that is being investigated, studied, and measured. It represents a quantity of something which value depends on how the independent variable is modified. It is usually identified by the letter Y.  A change in the dependent variable might be proportional or inversely proportional to the change in the manipulated variable. In the exposed example, the dependent variable is the egg circumference.

Constants / Controlled variables: Refers to those variables in an experiment that are controlled and have no influence on the results. These variables do not affect the change in the dependent variable values. In the exposed example the use of the lid to seal the jar and the amount and concentration of vinegar might be considered as a controlled variable. These elements are used but do not provoke any change in the size of the egg.

thats it... CAN SOMEONE ANSWER THE OTHERS?! I NEED ITT

4 0
3 years ago
If there are three methyl groups on the same carbon, what is the prefix<br> used?
Tanzania [10]

Answer:

tri

Explanation:

1-nothing

2-di

3-tri

- Hope that helps! Please let me know if you need further explanation.

6 0
3 years ago
What is the volume of the rock in the image in mL
Yuri [45]

Answer:

Initial volume: mL

Final volume: mL

Volume of rock: cm3

5 0
3 years ago
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