PLEASE HELP

Choose ALL TRUE statements about calorimetry from the choices below:

Ostrovityanka [42]

Answer:

True statment

2) Styrofoam would make a good calorimeter

3) Insulating material would make a good calorimeter

Explanation:

The calorimeter is one which is insulated that is which will not absorb or let the heat to escape from it. the calorimeter is used to measure the heat change during a process so if it will allow to exchange heat with surrounding it will deviate the readings or observence.

Copper is a good conductor of heat so we cannot use it make a calorimeter.

Hence

1) Copper would make a good calorimeter : False

2) Styrofoam would make a good calorimeter: True

Styrofoam is a bad conductor or insulator so it can be and it is used for calorimeter.

3) Insulating material would make a good calorimeter : True

4) A good calorimeter should easily absorb heat : false

6 0

3 years ago

In the process of attempting to characterize a substance, a chemist makes the following observations: (a) The substance is a sil

Amiraneli [1.4K]

The question is incomplete, this is the complete question;

In the process of attempting to characterize a substance, a chemist makes the following observations. Which are physical properties and which are chemical properties?

(a) The substance is a silvery white, lustrous metal.

(b) The substance melts at 649 ∘C

(c) The substance boils at 1105 ∘C.

(d) The density of the substance at 20 ∘C is 1.738 g/cm³.

(e) The substance burns in air, producing an intense white light.

(f) The substance reacts with chlorine to give a brittle white solid.

(g) The substance can be pounded into thin sheets or drawn into wires.

(h) The substance is a good conductor of electricity.

Answer:

(a) Physical

(b) Physical

(c) Physical

(d) Physical

(e) Chemical

(f) Chemical

(g) Physical

(h) Physical

Explanation:

(a) The substance is a silvery white, lustrous metal - is appearance which is physical.

(b) The substance melts at 649 ∘C metling point is a physical measurement

(c) The substance boils at 1105 ∘C boiling point is a physical measurement

(d) The density of the substance at 20 ∘C is 1.738 g/cm3 how heavy a substance is,is physical.

(e) The substance burns in air, producing an intense white light. Burning is a chemical change. It is a reaction of a substance with oxygen

(f) The substance reacts with chlorine to give a brittle white solid. This is a chemical reaction as the question says.

(g) The substance can be pounded into thin sheets or drawn into wires. Ductility is a physical change, the substance remains chemically unchanged

(h) The substance is a good conductor of electricity. Any conductivity is physical, the substance remains chemically unchanged

7 0

3 years ago

Advantages and disadvantages of using tidal energy instead of non-renewable energy sources.

Phantasy [73]

Advantages of using tidal energy:

-Environment-friendly

-A highly predictable energy source

-High energy density

-Operational and maintenance costs are low

-An inexhaustible source of energy

Disadvantages of using tidal energy:

-High tidal power plant construction costs.

-Negative influence on marine life forms.

-Location limits.

-The variable intensity of sea waves.

3 0

2 years ago

Refer to the periodic table tool and write the electron configurations of the following elements in both long and short terms

ahrayia [7]

Answer:-

Carbon

[He] 2s2 2p2

1s2 2s2 2p2.

potassium

[Ar] 4s1.

1s2 2s2 2p6 3s2 3p6 4s1

Explanation:-

For writing the short form of the electronic configuration we look for the nearest noble gas with atomic number less than the element in question. We subtract the atomic number of that noble gas from the atomic number of the element in question.

The extra electrons we then assign normally starting with using the row after the noble gas ends. We write the name of that noble gas in [brackets] and then write the electronic configuration.

For carbon with Z = 6 the nearest noble gas is Helium. It has the atomic number 2. Subtracting 6 – 2 we get 4 electrons. Helium lies in 1st row. Starting with 2, we get 2s2 2p2.

So the short term electronic configuration is [He] 2s2 2p2

Similarly, for potassium with Z = 19 the nearest noble gas is Argon. It has the atomic number 18. Subtracting 19-18 we get 1 electron. Argon lies in 3rd row. Starting with 4, we get 4s1.

So the short electronic configuration is [Ar] 4s1.

For long term electronic configuration we must write the electronic configuration of the noble gas as well.

So for Carbon it is 1s2 2s2 2p2.

For potassium it is 1s2 2s2 2p6 3s2 3p6 4s1

5 0

2 years ago

Compared to an endocrine response a nerve response differs in that the nerve response generally.

Nadusha1986 [10]

the nerve response is generally faster

Explanation:

nerves travel throughout neurotransmitters which is a faster response, like a reflex, than the hormones in the endocrine system, like the growth hormone.

7 0

3 years ago