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All the elements in group 18 are in a gaseous state (state true or false)
Answer:
The correct option is;
True
Explanation:
The noble gases are the group 18 elements, all of which are monoatomic gases, located in the extreme right of the periodic table. Due to their filled outermost or valence shells,and their nonreactive nature, the noble gases where initially known as inert gases.
The noble gases have very low melting points and boiling points as hey have very weak inter atomic forces between their atoms such that they all appear as gases under standard atmospheric temperature and pressure conditions.
how many w atoms are found in 0.43 moles of pure w
So, neon has a molar mass of 20.18 g/mol , which means that every mole of neon has a mass of 20.18 g . Now, you know that one mole of any element contains exactly 6.022⋅1023 atoms of that element - this is Avogadro's number.
Hope this helped
how many significant figures are in 340500
Answer:
there are 4
Explanation:
what atom has a greater number of neutrons
Answer:
livermorium
Explanation:
The atom with the largest number of neutrons is a tie between livermorium and tennessine. Each of these atoms contain 177 neutrons.
A sample of seawater weighs 158 g and has a volume of 156 mL. What is the density, in g/
mL, of seawater
1.01 g/ml
Hope this helps :)
A sample of seawater weighs 158 g and has a volume of 156 mL. The density of the seawater is 1.01 g/ml
What is density?Density is the mass per unit volume. Density is denoted by rho and the capital letter D. It can be calculated by dividing the mass by volume.
The volume is the space occupied by a three-dimensional object. It can be calculated by mass and density. It is measured in liters. Mass is the total weight of the object. It is denoted by m.
rho = m / V
rho = density
m = mass
V = volume
The given entities sample of seawater. Its weight is given and the volume is also given.
Given the mass of the sample of seawater weighs 158 mL g.
The volume is 156 ml.
Putting the values in the equation
D = 158 / 156 = 1.01 g/ml
Thus, the density of the seawater is 1.01 g/ml.
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Which is one way that scientists communicate the results of an experiment?
Answer:
firstly:scientist communicate with each other to share what they learn
secondly; they question and check each other's work
Answer:
Forming a hypothesis
Explanation:
Cuz why not
describe how 250 cm³ of 0.2 mol/dm³ H2SO4 could be prepared from 150 cm³ of 1.0mol/dm³ stock solution of the acid
Answer:
Explanation:
250 cm^3 of 0.2 moldm-3 H2SO4 can be prepared from 150cm^3 of 1.0 moldm^-3 by dilution.
150cm^3 of the 1.0 moldm^-3 stock solution is measured out using a measuring cylinder and transferred into a 250 cm^3 standard volumetric flask and made up to mark. The resulting solution is now 250cm^3 of 0.2 moldm-3 H2SO4.
Your mom gives you 6.20 moles of Dr. Pepper. How many particles is that?
Answer:
3.73E-22 particles
1 mole is equal to 6.022E-23 particles (known as avogadro's number). Multiplying 6.20 by 6.022E-23 will cancel out moles and give you particles.
Write a full equation for the reactions between magnesium and sulfuric acid
Explanation:
Hey there!!
See solutions in picture.
Hope it helps..
Express
[tex] {5}^{n + 2} - {5}^{n + 1} - {5}^{n} [/tex]
in the simplest form
Answer:
[tex]5^{n}[/tex]x19
Explanation:
[tex]5^{n+2}[/tex]-[tex]5^{n+1}[/tex]-[tex]5^n[/tex]
[tex]5^n[/tex](5²-[tex]5^{1}[/tex]-[tex]5^{0}[/tex])
[tex]5^n[/tex](25-5-1)
5^n(19)
[tex]5^{n}[/tex]x19
A regular solid measures 13.4 cm x 11.0 cm x 2.2cm. Calculate the volume of the solid.
Answer:
324.28 cm cubed
Explanation:
13.4 cm x 11.0cm x 2.2cm = 324.28 cm cubed
Which process is not one of the five general reaction types typically found in biochemistry? group transfers combustions isomerizations oxidation‑reduction reactions
Answer:
Option B (combustion) is the correct approach.
Explanation:
Combustion seems to be a procedure that requires fuel as well as an oxidizing agent response, during which the gaseous oxygen stores energy is set to release. Use a burning has been the oxidation of either fuel.Accelerated oxidizing combustion complemented by heat as well as, commonly, light. A biological confluence accompanied by temperature and light manufacturing process.Some other available scenarios have no connexons with the particular circumstance. So the obvious response to the above was its appropriate one.
Question 1
1. Mass reflects the amount of matter in an object.
True
False
Question 2
2. On Earth, your weight is exactly the same where ever you go.
True
False
Question 3
3. On Earth, your mass is exactly the same where ever you go.
True
False
Answer:
1. True.
2. False.
3. True.
Explanation:
1. Mass is simply defined as the quantity of matter present in a body. This means that mass gives us an idea of the amount of matter present in any object or body.
Therefore, the answer to the question is True.
2. Weight of an object is simply defined as the gravitational pull of the earth on an object. This implies that location of the object will greatly influence it's weight as the gravitational pull will varies from place to place. Hence, the weight of the object will differ as the location of the object changes.
Therefore, the answer to the question is False.
3. As defined above mass is the amount of matter present in an object.
The mass of an abject is constant irrespective of the location of the object.
Therefore, the answer to the question is True.
The helium-filled blimp shown in fig. p1.34 is used at various athletic events. determine the number of pounds of helium within it if its volume is 68,000 ft3 and the temperature and pressure are 80 f and 14.2 psia, respectively.
Answer:
The number of pounds of helium n = 666.995 lbm
Explanation:
Given that :
the volume V = 68000 ft³
the temperature T = 80 f = (80 + 460)°R =540°R
the pressure P = 14.2 psia
Using the ideal gas equation PV =nRT to determine the number of pounds of helium within, we have :
n = PV/RT
where;
R = 2.6809 psia. ft³/lbm.R (from the tables of A-1E for helium)
n = (14.2 × 68000)/(2.6809 × 540)
n = 965600/1447.686
n = 666.995 lbm
∴
The number of pounds of helium n = 666.995 lbm
A student wants to conduct an experiment to find out how pulse rate changes as the length of time spent exercising increases the dependent variable will be
Answer:
I'm not 100% percent sure what your question is, but here is what I think you are asking.
Explanation:
The dependent variable is pulse rate and the indepedent variable is the amount of exericse. The dependent variable changes as the independnet variable changes.
After which problem solving stage should you take action?
One must have to identify the issues first. Then he must measure the problem and then check out the available solutions. He must analyze the options and identify the correct one. After all these steps he can take the action.
The phase of any substance is dependent upon temperature and pressure.
True
False
Answer:
False
Explanation:
Answer:
false
Explanation:
pressure has nothing to do with the phases of a substance.
-20 points-
What chemical would dry ice be in if it were to turn into carbon dioxide?
Answer:
soild from carbon dioxide
What energy transfer is occurring when a battery-powered toy rolls across the floor? a Stored mechanical energy is converted to thermal energy. b Stored mechanical energy is converted to mechanical energy. c Stored chemical energy is converted to thermal energy. d Stored chemical energy is converted to mechanical energy.
Answer:
The correct option is;
d Stored chemical energy is converted to mechanical energy
Explanation:
Energy is stored in a battery in the form of electric potential energy. The chemical in a battery are such that they have an electric potential between them when charged and when the terminals of the battery are connected to an external circuit, the potential difference between the compounds at the poles causes electric current to flow from one pole, across the circuit and enter back into the battery through the other pole
The energy of the moving electrons can then be used to do mechanical work such as causing the mechanism of a coil in a magnetic field to rotate. The rotation can then be used to turn the wheels of the toy using gears.
what is the mass of 0.25 mol of sulfur atom
Answer:
8.0 g
Explanation:
To convert moles to grams, you need to use the molar mass. The molar mass of sulfur is 32.06. The molar mass is the atomic mass of the atom.
(0.25 mol) × (32.06 g/mol) = 8.015 g
Round for significant figures.
8.015 g ≈ 8.0 g
what kind of scientist would study the effects of acid rain on marble statues?
Answer:
A chemist
I hope this helped :D
Today you will be using the bunsen burner in your experiment. Which of the following is a precaution that should be taken before beginning?
Answer:
See the answer below
Explanation:
Although there are no specific options available to choose from, some of the general safety measures or precautions that must be observed when using a bunsen burner are as follows:
Always leave, at least, 12 inches of space between the bunsen burner and the nearest object. This is to avoid the nearby object catching fire accidentally.Always watch the flame at all times, never leave it unattended to.Burners should not be handled unless ample time has been given for them to cool down. This is to avoid burning-related injuries.Burner fittings should be carefully checked to ensure there are no leakages. Gas leakages may cause serious accidents.Always use a sparker as this is safer than using matches or lighter.The gas supply must always be turned off whenever the burner is not in use.For this experiment, students should wear a lab coat and safety eyewear. Students should not touch the flame. They need to keep loose clothing, jewelry, hair, and any flammable substances away from the flame.
You have 2.2 mol Xe and 2.0 mol F₂, but when you carry out the reaction you end up with only 0.25 mol XeF₄. What is the percent yield of this experiment? Xe(g) + 2 F₂ (g) → XeF₄ (g)
Answer:
The correct answer is 25 %
Explanation:
According to the chemical reaction:
Xe(g) + 2 F₂ (g) → XeF₄ (g)
1 mol of Xe(g) reacts with 2 mol of F₂(g), so the stoichiometric ratio os reactants is 2 mol F₂/mol Xe.
We have 2.2 mol Xe and 2.0 mol F₂, so the ratio is:
2.0 mol F₂/2.2 mol Xe = 0.909 mol F₂/mol Xe
The molar ratio of reactant we have is lower than the required, so F₂ is the limiting reactant.
By using the limiting reactant, we calculate the theoretical amount of product (XeF₄). For this, we know that 1 mol of XeF₄ is formed from 2 mol of F₂ (1 mol XeF₄/ 2 mol F₂), and we have 2.0 mol F₂:
2.0 mol F₂ x (1 mol XeF₄/ 2 mol F₂)= 1 mol XeF₄
If we only obtained 0.25 mol XeF₄, the percent yield of the experiment is:
Yield = experimental amount/theoretical amount x 100%
= 0.25 mol XeF₄/ 1 mol XeF₄ x 100% = 25 %
The percent yield of the solution is 25%.
The equation of the reaction is;
Xe(g) + 2F₂ (g) → XeF₄ (g)
From the reaction equation;
1 mole of Xe reacts with 2 moles of F2
2.2 moles of Xe will react with 2.2 moles × 2 moles /2 moles
= 4.4 moles of F2
We can see that there is not enough F2 hence it is the limiting reactant
2 moles of F2 yields 1 mole of XeF4
2 moles of F2 yields 2 moles × 1 mole/2 moles = 1 mole of XeF4
% yield = actual yield/Theoretical yield × 100
% yield = 0.25 mole/ 1mole × 100
% yield = 25%
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The standard enthalpy of formation (ΔHf°) of calcium carbonate is –1207 kJ/mol. Which ONE of the equations below has ΔH° = –1207 kJ? A) Ca(s) + C(s) + 3/2 O2(g) –––––> CaCO3(s) B) 2 Ca(s) + 2 C(s) + 3 O2(g) –––––> 2 CaCO3(s) C) Ca(s) + C(s) + 3 O(g) –––––> CaCO3(s) D) CaCO3(s) ––––> Ca(s) + C(s) + 3/2 O2(g) E) CaO(s) + CO2(g) –––––> CaCO3(s)
Answer:
A) Ca(s) + C(s) + 3/2 O₂(g) → CaCO₃(s)
Explanation:
Standard enthalpy of formation of a chemical is defined as the change in enthalpy durin the formation of 1 mole of the substance from its constituent elements in their standard states.
The consituent elements of calcium carbonate, CaCO₃, in their standard states (States you will find this pure elements in nature), are:
Ca(s), C(s) and O₂(g)
That means, the equation that represents standard enthalpy of CaCO₃ is:
A) Ca(s) + C(s) + 3/2 O₂(g) → CaCO₃(s)Is the equation that has ΔH° = -1207kJ/mol
The alpha decay of a radioactive nuclide (X) emits a He-4 nucleus and produces an isotope of Superscript 235 subscript 92 upper U.. What is X?
Answer: Thus X is Plutonium
Explanation:
Alpha Decay: In this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. The mass number is reduced by 4 units and atomic number is reduced by 2 units.
General representation of alpha decay :
[tex]_{Z}^{A}\textrm{X}\rightarrow _{Z-2}^{A-4}\textrm{Y}+_2^4\textrm{He}[/tex]
where Z = atomic number
A= mass number
X and Y = atomic symbol of elements
[tex]_{Z}^{A}\textrm{X}\rightarrow _{92}^{235}\textrm{U}+_2^4\textrm{He}[/tex]
Thus [tex]_{94}^{239}\textrm{Pu}\rightarrow _{92}^{235}\textrm{U}+_2^4\textrm{He}[/tex]
Thus X is Plutonium with atomic number 94 and mass number 239
Answer:
the answer is D on edge
Explanation:
Quantization of energy lab Hypothesis: Make a prediction that describes the relationship between the composition of an unknown substance and its emission spectrum. For example, “If each element can be identified by its ______________, then the ____________ of an unknown star can be determined." variables: independent - dependent- control-
Answer:
If each element can be identified by its spectrum then the composition of an unknown star can be determined
Explanation:
The chemical nature of the elements is that they absorb specific wavelength of light depending on their atom. By spectral analysis of the spectrum of emitted light by a body, the body's composition can therefore be determined. As such in order to determine the composition of distant bodies such as planets, stars and other celestial bodies scientists usually make use of spectroscopy.
Answer:
If each element can be identified by its spectrum then the composition of an unknown star can be determined
Explanation:
Now select a longer period, say the fourth period, starting with the element in the 1A group. Again, go from left to right. What do you notice about the pattern of change in the electron configuration as you go from left to right?
Answer:
The pattern of change in the electron configuration increases from left to right across the period.
Explanation:
In the periodic table, elements having the same number of electrons in the outermost shell of their atoms are placed over one another in vertical columns. Each of the vertical columns is known as a group or family. while each of the resulting horizontal rows is known as a period or row.
There are 18 vertical columns and seven periods in the periodic table. Each period begins with an atom having a valence electron and ends with an atom having a complete outer shell structure of an inert gas.
The fourth period of the periodic table (d-block) consists of the transition elements.
The electron distribution into the energy levels of sublevels of atoms can be shown in any of the tree important electronic configuration.
Electronic configuration shows the sequence of filling electrons into the orbitals of the sublevels as guided by some principles.
The maximum number of electrons in the orbitals of sublevels are two for s-sublevel(one orbital) ; six for p-sublevel( three orbital); ten for d-sublevel ( five orbitals) and fourteen for f-sublevel( seven orbitals). This indicates that the maximum number of electrons in an orbital is two
In the Periodic table ,The sublevels with lower energies are filled up before those with higher energies. One important thing about this principle is that the sublevels do not fill up in numerical order. The pattern of filling is as follows:
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f etc.
Answer:
In the electron configuration of potassium, I observe that after the 3p orbital is filled, the next electron enters the 4s orbital instead of the 3d orbital because 3d is at a higher energy than 4s. This pattern shows that orbitals fill up according to the Aufbau principle. As I move on right, the number of electrons increases by one for each element until vanadium is reached. The electron configuration of chromium shows all Half-filled orbitals in the 4s and 3d energy levels. Again, as I move right, an exception occurs at copper. Copper’s electron configuration shows completely filled 4s and 3d orbitals. This is an exception to the Aufbau principle to attain more stable electron configurations, whenever possible. Half-filled electron configurations are more stable than other configurations and completely filled electron configurations are the most stable.
Which part of an investigation is obly found in an experimental investigation?
A. a hypothesis
B. a control group
C. a procedure
D. a conclusion
Answer:
B
Explanation:
The control group is the only answer given that would be found in an experimental investigation. This is because it won't be changed during the experiment. It will remain neutral.
In descriptive scientific investigations, scientists often make observations to understand the interacting parts of a complex (blank)
Answer:
Complex System
Explanation:
Given that, a descriptive scientific investigation is one of the three main types of investigation which formulates and quantify the natural phenomenon. This natural phenomenon oftentimes involves Complex System, such as microscopic organisms, thereby, scientists often make observations to understand the interacting parts of this COMPLEX SYSTEM
Hence, the right answer is a COMPLEX SYSTEM
LC Chemistry I v18 (GS) / Module 01: Matter
1.(01.05 LC)
Which of the following is an example of a chemical change? (4 points)
Boiling water
Burning paper
Dissolving sugar in water
Melting gold
Answer:
Burning Paper
Explanation:
Burning Paper is an example of a chemical change because;
- A new substance called ''Ash'' is formed.
- It is an irreversible reaction.