Answer: Lavoisier organized a list of the known elements of his day as four categories. Newlands was the first to organize the elements and show that properties repeated in a periodic way. Mendeleev and Meyer proposed periodic tables showing a relationship between atomic mass and elemental properties. Moseley organized the elements by atomic number instead of atomic mass.
Explanation:
Question 6 of 10
How much energy is required to vaporize 2 kg of gold? Use the table below
and this equation: Q = mLvapor
Substance
Latent Heat
Fusion
(melting)
(kJ/kg)
Melting
Point
(°C)
Latent Heat
Vaporization
(boiling) (kJ/kg)
Boiling
Point
(°C)
Aluminum
400
660
1100
2450
Copper
207
1083
4730
2566
Gold
628
1063
1720
2808
Helium
52
-270
21
-269
Lead
24.5
327
871
1751
Mercury
11.4
-39
296
357
Water
335
0
2256
100
Answer: Q = mlvap
Q = (2 kg)(1 kmol/197 kg)(1,000 mol/1 kmol)
Q = 10.15 kJ
2126 joules of energy in form of thermal energy is required to vaporize 2 kg of gold.
What is thermal energy?Thermal energy is defined as a type of energy which is contained within a system which is responsible for temperature rise.Heat is a type of thermal energy.It is concerned with the first law of thermodynamics.
Thermal energy arises from friction and drag.It includes the internal energy or enthalpy of a body of matter and radiation.It is related to internal energy and heat .It arises when a substance whose molecules or atoms are vibrating faster.
These vibrating molecules and atoms collide and as a result of which heat is generated in a substance , more the collision of particles , higher is the thermal energy.
Amount of heat is calculated as, Q=2×1063 =2126 joules as per the given formula.
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How many moles are there in 4.9x10^23 molecules of CO2?
F. 0.81 moles of CO2
G 8.14X10^45
H. 2.95X10^47
J. 2052.44
Answer:
0.81 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\ [/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{4.9 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{4.9}{6.02} \\ = 0.813953...[/tex]
We have the final answer as
0.81 molesHope this helps you
Iron has a density of 7.87 g/cm^3. What is the mass of 55.2 cm^3 of iron?
Answer: Formula: Mass = (Volume)(Density)
Iron Density = 7.87 g/cm^3
Volume of Iron = 55.2 cm^3
Mass=(V)(D)
Mass= (55.2 cm^3) x (7.87 g/cm^3)
Mass= 434,42 g
Explanation:
Iron has a density of 7.87 g/cm³. 434,42 g is the mass of 55.2 cm³ of iron.
What do you mean by density ?The term density is defined as the measurement of how closely a material is packed together.
It is also defined as the mass per unit volume. Density Symbol is D or ρ Density Formula is ρ = m/V, where ρ is the density, m is the mass of the object and V is the volume of the object.
Density is an important because it allows us to find out what substances will float and what substances will sink when placed in a liquid.
Formula:
Mass = (Volume)(Density)
Given:
Iron Density = 7.87 g/cm³
Volume of Iron = 55.2 cm³
Mass=(V)(D)
Mass= (55.2 cm³) x (7.87 g/cm³)
Mass= 434,42 g
Thus, Iron has a density of 7.87 g/cm³. 434,42 g is the mass of 55.2 cm³ of iron.
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Identify the most and the least basic compound in each of the following sets. Leave the remaining answer in each set blank. a) Sodium acetate: _______ Ammonia: _______ Sodium ethoxide: _______ b) Sodium acetate: _______ Sodium chloroacetate: _______ Sodium fluoroacetate: _______ c) Sodium acetate: _______ Sodium methoxide: _______ Sodium phenoxide:
Answer:
The correct answer is -
a) Sodium acetate: least Ammonia: _______ Sodium ethoxide: most
b) Sodium acetate: most Sodium chloroacetate: _______ Sodium fluoroacetate: least
c) Sodium acetate: least Sodium methoxide: most Sodium phenoxide:
Explanation:
A) In this case the basicity can be found by the stability of the base, Sodium acetate is the most stable base due to resonance stabilization of acetate anion. Sodium acetate is the least basic as the lone pair of electrons involved in the resonance here. An ethoxide ion has more electrons to donate an electron pair easily.
Thus, the correct answer is - Sodium acetate is the least basic while sodium ethoxide is the most basic.
B) Fluroacetate gives a very strong acid and the acetate gives the least strong acid among all three as described in case of a), thus, the most basic is acetate and the least is fluoroacetate.
]C) comparing the acidity of the acids formed by the addition of a proton to the anions is an easy and correct way to find the basicity of compounds.
Acetate ion adds a proton ⇒ acetic acid
methoxide adds a proton ⇒ methanol
phenoxide ion adds proton ⇒ phenol
As it is known that the stronger the acid, the weaker is the conjugate base formed by the loss of the proton.
acetic acid is the strongest acid because it can easily give up its proton to form acetate. Methanol is the weakest among all three and hence methoxide anion is the strongest base.
Thus, the correct answer is - sodium acetate is the least basic while sodium methoxide is the most basic.
are two double bonds in
uble dash.
:0=C=O
NO2-
Answer:
Yes
Explanation:
There are in double dash :) ( = )
Answer:
yes
Explanation:
Because the double dash shows a double bond it simply means that two electrons from each atom are being shared
The spinning of Earth on its axis is an example of its ________.
Answer:
rotation
Explanation:
Answer:
Rotation
Explanation:
Earth rotates on it's axis to give us the day and night cycle
The precision of a method is being established, and the
following
data are obtained 22.23, 22.18 22.25, 22.09
and 22.15%, is 22.09% a valid measurement?
Answer:
No, 22.09% is not a valid measurement
Explanation:
Precision has to do with how close a given set of measured values are to each other. It is quite different from accuracy. Accuracy refers to how close a given set of values is to the true value. A given set of values may be precise but not accurate and vice versa.
If we look at the values obtained; 22.09%, 22.15%, 22.18%, 22.23%, 22.25%, the value 22.09% is too far off the other values. This implies that it does not represent a valid measurement since it is not close to all the other values obtained.
identify the solute in the following: carbon dioxide dissolved in water
a. water
b. carbon dioxide
c. none of the above
d. carbon dioxide and water
Answer:
B
Explanation:
its solute state is gas and dissolve in (solvent) liquid which is water
which part of the human nervous system links the brain to the rest of the body
Digaments
spindi cord
heart
Answer: The Spinal Cord
Explanation: The spinal cord runs along the dorsal side of the body and links the brain to the rest of the body.
Write a balanced net ionic equation.
Na3PO4(aq) + FeCl3(aq) = NaCl(aq) + FePO4(s)
Explanation:
Na3PO4+ FeCl3 = 3NaCl + FePO4
Hope it will help :)❤
The net ionic equation is found to be balanced by both mass and charge. There are equal masses of each element on the product and reactant sides in a balanced net ionic equation.
What is a net ionic equation?A chemical equation which shows only those elements, compounds, and ions which are directly involved in the chemical reaction is defined as the net ionic equation. The net ionic equation give us information about the ions that exists in aqueous medium.
A net ionic equation does not consider the spectator ions. The ions which do not participate in chemical reactions and are seen on both sides of the reactions are called spectator ions.
The complete ionic equation for the given reaction is:
3Na⁺ (aq) + PO₄³⁻ (aq) + Fe³⁺ (aq) + 3Cl⁻ (aq) → 3Na⁺ (aq) + 3Cl⁻ (aq) + FePO₄ (s)
The net ionic equation is:
PO₄³⁻ (aq) + Fe³⁺ (aq) → FePO₄ (s)
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The trait that seems to fade into the background.
Dominant
Recessive
How many particles of ZnCrO4 are present in a 4.5 mole sample?
2.7 × 10²⁴ particles ZnCrO₄
General Formulas and Concepts:Chemistry
Atomic Structure
MolesAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
[Given] 4.5 mol ZnCrO₄
[Solve] particles ZnCrO₄
Step 2: Identify Conversions
Avogadro's Number
Step 3: Convert
[DA] Set up: [tex]\displaystyle 4.5 \ mol \ ZnCrO_4(\frac{6.022 \cdot 10^{23} \ particles \ ZnCrO_4}{1 \ mol \ ZnCrO_4})[/tex][DA] Multiply [Cancel out units]: [tex]\displaystyle 2.7099 \cdot 10^{24} \ particles \ ZnCrO_4[/tex]Step 4: Check
Follow sig fig rules and round. We are given 2 sig figs.
2.7099 × 10²⁴ particles ZnCrO₄ ≈ 2.7 × 10²⁴ particles ZnCrO₄
What is the chemical formula for an acid?
I have a lab report I have to do for Chemistry on Edge, the lab is on Enthalpy.
please let me know if you need further information.
Answer:
I need further information.
Explanation:
Extra information is needed for you to know the correct information.
What is Enthalpy?It is a thermodynamic quantity that is equal to the total heat content of a system. It is equal to the internal energy of the system plus the product of pressure and volume.
Enthalpy is nothing but energy and they are of 4 types in thermodynamics-
1. Internal Energy, U
2. Heat enthalpy, H
3. Helmholtz enthalpy, A
4. Gibb's Free enthalpy, G
The total energy of a system cannot be measured directly because the internal energy contains components that are unknown, not easily accessible, or are not of interest in thermodynamics. Generally, a change in enthalpy is the expression for measurements at constant pressure because it simplifies the information of energy transfer.
Therefore, Extra information is needed for you to know the correct information.
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In an experiment, 135.2 grams of a mystery metal is heated to 100.0*C. The metal is then dumped into a calorimeter with 59.0 grams of water at 26.0*C. The temperature of the water in the calorimeter increases to 35.0*C after the metal is dumped into it. What is the specific heat capacity of the metal? Express your answer to 2 past the decimal. Do NOT include units
A change in velocity can occur without a change in speed *
A: True
B: False?
Answer: True
Explanation: For example, changing direction can change velocity
if 23.1g of O2 occupies a volume of 5.0L at a particular temperature and pressure, what volume will 2.50g of Oxygen gas occupy under the same conditions?
Answer:
0.54 L
Explanation:
First we convert the given masses of O₂ into moles, using its molar mass:
23.1 g ÷ 32 g/mol = 0.722 mol2.50 g ÷ 32 g/mol = 0.078 molThen we can solve the problem using Avogadro's law, which states:
V₁n₂=V₂n₁Where:
V₁ = 5.0 Ln₂ = 0.078 molV₂ = ?n₁ = 0.722 molWe input the data:
5.0 L * 0.078 mol = V₂ * 0.722 molAnd solve for V₂:
V₂ = 0.54 LFrom these four cycles which are water cycle, carbon cycle, nitrogen cycle, and phosphorus cycle which cycle has more nutrients
Answer:
Nitrogen cycle
Explanation:
2 Nal + Pb(NO3)2
2 NaNO3
+
Pb12
What are the reactants in this equation?
Answer:
[tex]\boxed {\boxed {\sf A. \ NaI \ and \ Pb(NO_3)_2}}[/tex]
Explanation:
In a chemical reaction, the reactants are the substances that start the reaction and change into other substances. The results at the end of the reaction are products.
Typically, the reactants are to the left of the arrow, while products are to the right.
reactants ⇒ productsWe are given this chemical equation:
[tex]2 \ NaI + Pb(NO_3)_2 \rightarrow 2NaNO_3 +PbI_2[/tex]
We are asked to find the reactants. Remember, these go into the reaction and are on the left.
[tex]\bold {2 \ NaI + Pb(NO_3)_2 } \rightarrow 2NaNO_3 +PbI_2[/tex]
Therefore, the reactants are NaI (sodium iodide) and Pb(NO₃)₂ (lead nitrate). Choice A is correct.
HELPPPP ASAP!!! Plzzz
Answer:
420 miles
Explanation:
From the question given above, the following data were obtained:
Time = 3.5 hours
Speed = 120 mi/h
Distance =?
Speed is defined as the distance travelled per unit time. Mathematically, it is expressed as:
Speed = distance / time
With the above formula, we can obtain the distance travelled by the plane as follow:
Time = 3.5 hours
Speed = 120 mi/h
Distance =?
Speed = distance / time
120 = distance / 3.5
Cross multiply
Distance = 120 × 3.5
Distance = 420 miles
Thus, the distance travelled by the plane is 420 miles
Helllllp me please
Part D ends with neon Express your answer as an integer. 20
Answer:
attach file please
25 ml of liquid and has a mass of 19 grams. Calculate the density.
What is the ratio by atoms of elements present in technetium (VII) peroxide? (peroxide
is a polyatomic ion)
1:7
2:8
4:9
3:1
Answer: 1:7
Explanation: 2 Tc^+7 + 7 O2^-2 -> Tc2 (O2)7
Also 2 Tc to 14 O
thesis: physical science improves nursing through technology, energy, and Matter.
write a 4-page essay explaining how science improves Nursing career and how it revolves around
Technology
Energy
Matter
Answer:
When science educators teach nurses, their primary aim should be to help them to develop understanding of their world of nursing. From a study of registered nurses' conceptions of the physical science underlying their clinical practice, we assert that nurses' understanding of the physical sciences is inadequate in terms of the competencies required of them as nurses.
Explanation: Hopes this helps You A lot :-D
2. What organelle in plant cells makes it possible for plants to carry out photosynthesis?
a. cell wall
b. chloroplast
C. lysosome
d. nucleus
Calculate the percent by mass of the solute in an aqueous solution of 27.2 g ethanol in 250 g of total solution.
Answer:
Explanation:
H
Mass percent can be calculated from the mass of solute in grams divided by the mass of solution multiplied by 100. The percent by mass of the solute in aqueous solution of 27.2 g ethanol in 250 g of total solution 10.88 %.
What is mass percentage?Mass percentage is term used to represent the concentration of a solution. Mathematically mass percent of a component in a mixture is the mass of the component divided by the total mass multiplied by 100.
A solution is made of a solvent and solute. Thus, the total mass of the solution is the sum of mass of solute and mass of the solvent. Here, the solute is ethanol with a mass of 27.2 g. The total mass of solution is 250g.Hence, the mass percent of ethanol can be calculated as follows:
Mass percent of ethanol = mass of ethanol/total mass ×100
= (27.2/250)×100
= 10.88 %.
Hence, the percent by mass of solute ethanol in the total solution is 10.88%.
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1. What volume of a 2.50M Kl(aq) is needed to make 200 ml of a 1.OOM KI)aq)?
Answer:
80 ml
Explanation:
From the question,
Applying Dilution formular
MV = mv................... Equation 1
Where M = Molarity of Kl before dilution, V = Volume of Kl before dilution, m = molarity of Kl after dilution, v = volume of Kl after dilution.
make V the subject of the equation
V = mv/M............. Equation 2
Given: m = 1.00 M, v = 200 ml, M = 2.50 M
Substitute these values into equation 2
V = (1.00×200)/2.50
V = 80 ml
gases are really _______ and molecules are full of _______, bouncing around constantly
Answer:Gases are really spread out and the atoms and molecules are full of energy - , bouncing around constantly.
Explanation:
A truck accelerates at a rate of 14 m/s2 . The truck weighs 17000 kg. What is the amount of force
necessary for the truck to accelerate at this rate?
Answer:
238000 N
Explanation:
Use F=ma
Mass= 17000 kg
Accel.= 14 m/s²
Tarnish on silver is the compound Ag2OAg2O. A tarnished silver spoon is placed in an aluminum pan of boiling water. When enough salt is added so that the solution conducts electricity, the tarnish disappears. Imagine that the two halves of this redox reaction were separated and connected with a wire and a salt bridge.
Answer:
The answer is "2.459".
Explanation:
The cell potential or emf norm = oxidation pot. of anode -oxidation pot. of cathode
When the pot oxidizer is the opposite of a red pot size it's been transformed to either the redox reaction so that anode was its higher oxide pot material that means (AL) so,
[tex]\to emf=1.66-(-0.799) \\\\ \to emf=1.66+0.799) \\\\ \to emf =2.459[/tex]