Answer:
Mass of Cr= 78 g
Explanation:
Given data:
Specific heat of Cr = 0.448 j/g.°C
Initial temperature of Cr lump = 89.5°C
Mass of water = 75.2 mL or 75.2 g
Initial temperature of water = 20.5°C
Final temperature of water = 27.4°C
Mass of Cr = ?
Solution:
when we placed the lump of Cr metal into water heat lost by limp is equal to the heat gain by water.
Specific heat capacity of water is 4.184 j/g.°C
Q = mcΔT
Q = 75.2 g× 4.184 j/g.°C × (27.4°C - 20.5°C)
Q = 2171 J
Heat lost by Cr lump is -2171 J. Now we will calculate the mass of Cr.
Q = mcΔT
-2171 J = m ×0.448 j/g.°C × ( 27.4°C- 89.5°C)
-2171 J = m × -27.821 j/g
m = -2171 J/-27.821 j/g
m = 78 g
How does the atomic radii trend explain the electronegativity trend?
Answer: electronegativity decreases.
Explanation: This is because atomic number increases down a group, and thus there is an increased distance between the valence electrons and nucleus, or a greater atomic radius.
While designing his recording studio, Brian was trying to determine what type of surface he should use for his studio walls. He wanted to be able to produce clear, crisp, sound. So he needed a surface that wouldn't cause his music to echo. What type of surface should Brian use for his studio walls?
Answer: Acoustic Foam.
Explanation:
Acoustic Foam: This is a kind of material, which is commonly known as it called a Studio Foam, it has a kind of wedge or pyramid shape that plays a big role in absorbing sound. Brian would have to use acoustic foam by placing them round the walls and ceiling as this would stop any echoing sound and in return give a crisp and clear sound when music is been played it the studio.
What is the correct value using 3 significant figures for 14.8232 g/mol?
Answer:
14.8 g/mol
Explanation:
Starting on the left, count in 3 numbers (14.8), then round using the next number (0.02).
Because 2 is less than 5, the number stays the same and is not rounded up.
Which descriptions apply to prokaryotic cells? Check all that apply.
are usually single-celled
contain a nucleus
do not contain membrane-bound organelles
have DNA located in cytoplasm
Answer:
-are usually single celled
-do not contain membrane-bound organelles
-have DNA located in cytoplasm
Explanation:
currently taking the test
What is meant by a solute-give an exmple.
What is meant by a solvent - give an exemple
what is meant by a solution -give an exmple
what do the following symbole mean s,l,g and aq
what is the difference between filtration and crystallisation
Answer:
A solute is a substance that dissolves in a solvent to for a solution.Example; Sugar.
A solvent is a substance that dissolves a solute to form a solution.Example ;water.
A solution is a uniform mixture of a solute and a solvent.
aq means aqueous
In fiteration the residues are called filtrates but in crystalization the residues are called crystals .
Enter the symbol of the element which would have 36 electrons and -3 charge.
Answer:
Arsenic if I understood correctly
Explanation:
Ions can be made by single element or covalently bonded group of elements. The covalently bonded group of elements is called polyatomic ions or polyatomic atoms. Therefore, the element with atomic number 33 and -3 charge is Arsenic.
What is Ions?Any species that contain charge whether it is positive charge or negative charge is called ions. The example of polyatomic ions are sulfate, phosphate, nitrate etc.
Cation is the species that loose electron and attain positive charge while anion is a species which gain electron and attains negative charge so when anion and cation combine in fixed ration the the overall charge of the molecule is zero that is molecule is neutral, the charge over cation and anion is also called oxidation state. The element with atomic number 33 and -3 charge is Arsenic.
Therefore, the element with atomic number 33 and -3 charge is Arsenic.
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Is burning the glass plate is physical or chemical change?
the graph below shows the effect of temperature the volume of gas
Which generalization can be made about the relationship between the temperature and volume of a gas?
A. As the temperature of a gas increases, its volume increases.
B. As the temperature of a gas decreases, its volume increases.
C. As the temperature of gas decreases, its volume stays the same.
D. As the temperature of a gas increases, its volume stays the same.
Answer:
as the temperature of gas increases, its volume stays the same
Explanation:
Answer:
A! :)
Explanation:
This picture shows a model if a cell. What is the main function of the part labeled Z in the model?
Answer:
store water so b
Explanation:
labeled Z in the model refers to store food and other material in the cell.
what is cell?
cell can be defined as the basic unit of the living cell, it can be unicellular or multicellular. unicellular organism are prokaryote and some of the unicellular eukaryotes whereas multicellular organisms are eukaryotes like plants and animals.
a basic component of cell are cell membrane, cytoplasm, nucleus, mitochondria, lysosome, golgi body, endoplasmic reticulum.
cell wall only present in plant cell and prokaryotic cell while it is absent in animal cell, the function of cell wall is to provide protection
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what is the median number of 69,64,63,66?
when heat is added to a substance describe how the molecules are affected?
Answer:
the molecules and atoms start to vibrate faster so basically the object starts to expand because the space between atoms increases :)
An ideal sample weighing 1.28g at 127C (temp) and 1 atm has a volume of 0.250L. Determine the molar mass of the gas.
Answer:
Molar mass of gas = 160 g/mol
Explanation:
Given data:
Mass of sample gas = 1.28 g
Temperature of sample gas = 127°C (127+273 = 400K)
Pressure of sample gas = 1 atm
Volume of sample gas = 0.250 L
Molar mass of gas = ?
Solution:
Formula:
PV = nRT
R = general gas constant = 0.0821 atm.L/ mol.K
Now we will put the values in formula.
1 atm × 0.250 L = n × 0.0821 atm.L/ mol.K ×400K
0.250 L.atm = n ×32.84atm.L/ mol
n = 0.250 L.atm/32.84atm.L/ mol
n = 0.008 mol
Molar mass of gas:
Number of moles = Mass/molar mass
0.008 mol = 1.28 g / molar mass
Molar mass = 1.28 g / 0.008 mol
Molar mass = 160 g/mol
Which of the following is an example of very early scientific research?
sleeping in caves to avoid predation by animals
painting pictures and symbols on cave walls
making baskets from reeds
banging rocks together to see which make a spark and create fire
Answer:
banging rocks together to see which make make a spark and create fire painting pictures is an example of art and sleeping in caves is survival
Quick
Choch
Place each description in the correct category.
represented by symbols
Elements
Compounds
made of one type of atom
represented by formulas
cannot be broken down
can be chemically broken down
made of two or more types of atoms
Answer:
a i believe
Explanation:
a
what are these significant figs A) 0.0040 B)1,000,000 C) 1.20 X 10^3
the mass of an atomic number best refers to the number of
Answer:
Mass number
Explanation:
Students were investigating properties of matter, but wanted to make sure that when they tested these properties they had properties that would represent the matter they were testing specifically. The students claim that they are going to test intrinsic properties. What evidence and reasoning would you provide to justify this claim? (7 points)
Answer:
See explanation
Explanation:
An intrinsic property is a property that is internal, that is, it characterizes the substance under study. The possession of an intrinsic property depends on the nature of the substance. An intrinsic property does not depend on amount of substance but on the nature of the substance.
Examples of intrinsic properties include; Density. Solubility, Melting Point, Freezing Point, Boiling Point, Conductivity etc.
Intrinsic properties really represent the matter that is being studied. For instance, the boiling point of water will always be 100°c. No other liquid can boil exactly at that temperature. Hence, this intrinsic property can always be used to identify an unknown liquid as water.
The students were right, studying intrinsic properties accurately represent the matter that is being studied.
Please help!
We are doing a lab and I have trouble doing the data analysis. Using my data collection, Can you guys help me using the MC delta T equation?
4.94 x c . (Tm-23.6)=C.(23-6-21.9)+123.13 x c. (23.6-21.9)
Further explanationThe law of conservation of energy can be applied to heat changes, ie the heat received/absorbed is the same as the heat released
Q in = Q out
Heat can be calculated using the formula:
Q = mc∆T
A calorimeter is a device used to measure the specific heat of material
A metal is put into a calorimeter that contains water and there will be heat transfer:
[tex]\tt \displaystyle m_mc_m (T_m-T)=m_wc_w(T-Tw)[/tex]
m = metal
w = water
T = the final temperature of the mixture
mass of metal =(Nickel) = 4.94 g
mass of calorimeter = 12.5 g
mass of water = 123.13 g (135.63 - 12.5)
The equation
Q released (metal) = Q absorbed(calorimeter+water)
Qmetal = 4.94 x c . (Tm-23.60)Q calorimeter = C.(23-6-21.9) --> C = heat capacity of calorimeterQ water = 123.13 x c. (23.6-21.9)The equation :
4.94 x c . (Tm-23.6)=C.(23-6-21.9)+123.13 x c. (23.6-21.9)
Coffee is an example of a
a
homogeneous mixture
b
heterogeneous mixture
c
suspension
d
colloid
Answer:
A
Explanation:
Which answer choice correctly describes what will happen to an element with four valence electrons if it engages in a chemical reaction?
a. It will lose electrons.
b. It will neither gain nor lose electrons.
c. It will gain electrons.
d. It may gain or lose electrons.
Which of the following presents the steps of the engineering process in the correct order?
1.Identify a need, make a plan know the background, do the work, test the results, evaluate and redesign
O
2. dentify a need, know the background, do the work, make a plan, evaluate and redesign, test the results
3. Know the background, identify a need, make a plan, evaluate and redesign, do the work, test the results
4.Identify a need, know the background, make a plan, do the work, test the results, evaluate and redesign
Answer:
4
Explanation:
I got it right
The engineering process in the correct order "Identify a need, know the background, make a plan, do the work, test the results, evaluate and redesign"
What is engineering process?At an industrial level, process engineering is just the understanding as well as application of fundamental natural principles and laws that allow people to transform raw materials along with energy into products that seem to be beneficial to society.
What is redesign?Redesign, in terms of building, is the procedure of finding a solution to such a project. this includes then writing instructions that allow such a solution to be built.
The engineering process in the correct order "Identify a need, know the background, make a plan, do the work, test the results, evaluate and redesign"
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Explain Newton's first law of motion. Write your answer in the essay box below.
Answer:
I hope this helps :D
Explanation:
Newton's first law expresses that each object will stay very still or in uniform movement in an orderly fashion except if constrained to change its state by the activity of an outside power. ... The third law expresses that for each activity (power) in nature there is an equivalent and inverse response.
For the reaction 2NH3(g)↽−−⇀3H2(g)+N2(g) 2 NH 3 ( g ) ↽ − − ⇀ 3 H 2 ( g ) + N 2 ( g ) the equilibrium concentrations were found to be [NH3]=0.250 M, [ NH 3 ] = 0.250 M, [H2]=0.300 M, [ H 2 ] = 0.300 M, and [N2]=0.750 M. [ N 2 ] = 0.750 M. What is the equilibrium constant for this reaction? c= K c =
Answer:
0.324
Explanation:
The following data were obtained from the question:
Concentration of NH3, [NH3] = 0.25 M
Concentration of H2, [H2] = 0.3 M
Concentration of N2, [N2] = 0.75 M
Equilibrium constant (Kc) =.?
The balanced equation for the reaction is given below:
2NH3 <==> 3H2 + N2
The equilibrium constant, Kc for a given reaction is the ratio of the concentration of the products raised to their coefficient to the concentration of the reactants raised to their coefficient. Thus, the equilibrium constant for the above reaction can be obtained as illustrated below:
Kc = [H2]³ [N2] / [NH3]²
Concentration of NH3, [NH3] = 0.25 M
Concentration of H2, [H2] = 0.3 M
Concentration of N2, [N2] = 0.75 M
Equilibrium constant (Kc) =.?
Kc = [H2]³ [N2] / [NH3]²
Kc = [0.3]³ × [0.75] / [0.25]²
Kc = (0.027 × 0.75) / 0.0625
Kc = 0.02025 / 0.0625
Kc = 0.324
Therefore, the equilibrium constant for the reaction is 0.324
According to Dalton’s atomic theory, what are elements and what makes one element different from another?
Dalton was a chemist who discovered the “law of multiple proportion” in chemical reaction in early nineteenth century. For example, element of tin, he observed, interacted with oxygen to produce two different masses but in proportion 1:2. (Now, this is known to correspond to the formation of tin-monoxide and tin-dioxide, with one and two atoms of oxygen, respectively.)
From such and related studies, he proposed his theory of chemical elements: (a) that all elements are composed of ‘atoms’, the hypothetical indivisible constituents of matter of the ancient Greek thinkers, like, Democritus, and (b) that the elements differ from one another due to the atoms of different masses and sizes that constitute an element.
The modern theory of chemistry says that an element consists of an atom that consists of a heavy nucleus with positively charged ‘protons’ (and most often also the neutral particles called ‘neutrons’) at its center and, an equal number of negatively charged (and much lighter) ‘electrons’, distributed around it in discrete energy shells. Further, the elements differ from one another by the number of positively charged protons in their nucleus, the so-called atomic number, Z, of an atom. Finally, molecules are formed as well as chemical reactions take place, through the exchange or transfer of the electron(s) in the outermost shells of the reacting atoms (and/or molecules).
Please answer it correctly and explain clearly
Answer:
i think that the children will inherit the brown eyes, it is the best answer since the other things cant be inherited and he dyed his hair blonde
Explanation:
According to the law of conversion of mass in a chemical equation
3. Which of the following does not affect the solubility of solid solutes?
a. Volume of solvent
b. Stirring
c. Temperature
d. Amount of solvent
Answer:
Temperature
Explanation:
i GUESS that's the ans lol sry I needed points
what property of matter describe how matter reacts with other matter ?
a.flammable
b.color
c.shape
d.volume
Answer:
Flammability
Explanation:
Flammability is a chemical property. So, this means that it must react with a substance.
Color, shape, and volume are physical traits. This means that no other matter needs to be included in order for this trait to be so.
Sodium electron configuration in longhand notation
Answer:
Na₁₁ = 1s² 2s² 2p⁶ 3s¹
Explanation:
Sodium is present in group 1.
It is alkali metal.
It has one valence electron.
The atomic number of sodium is 11.
Its atomic mass is 23 amu.
The longhand notation of electronic configuration of sodium can be written as,
Na₁₁ = 1s² 2s² 2p⁶ 3s¹
The electronic configuration in shorthand notation( noble gas) would be written as,
Na₁₁ = [Ne] 3s¹
Sodium loses its one valence electron to complete the octet and get stable thus form +1 cation.
It react with halogen and form salt. Such as sodium chloride.
2Na + Cl₂ → 2NaCl
Which of the following is the final stage of a low mass star? *
1 point