The elements in the lanthanide series are similar to gadolinium.
The periodic table is arranged in groups and periods. Elements in the same group have similar properties. At the bottom row of the periodic table lies a group of elements that have unique properties called the lanthanides. This is where Gadolinium belongs.
The elements in the lanthanide series such as europium and terbium are similar to gadolinium. The lanthanides are similar in chemical reactivity and appearance. However, the density of the metals differ because it increases with increase in atomic number.
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Use the heat equation to find out how many joules of energy are needed
to raise the temperature of 67 grams of water form 20°C - 45°C. What is the
answer in kilojoules?
(specific heat of water is 4.2 J/gºC.)
Answer:
About 7.0 × 10³ J or 7.0 kJ
Explanation:
We want to determine the amount of energy needed to raise the temperature of 67 grams of water from 20°C to 45°C.
We can use the heat equation:
[tex]\displaystyle q = mC\Delta T[/tex]
Where C is the specific heat of water.
Substitute and evaluate:
[tex]\displaystyle \begin{aligned} q & = (67\text{ g})\left(\frac{4.2\text{ J}}{\text{g-$^\circ$C}}\right)\left(45^\circ \text{ C}- 20.^\circ\text{ C}\right) \\ \\ & = (67\text{ g})\left(\frac{4.2\text{ J}}{\text{g-$^\circ$C}}\right)(25^\circ \text{ C}) \\ \\ & = 7.0\times 10^3 \text{ J}\end{aligned}[/tex]
Recall that there are 1000 J in a kJ. Hence:
[tex]\displaystyle \begin{aligned} q & = 7.0\times 10^3 \text{ J} \cdot \frac{1\text{ kJ}}{1000\text{ J}} \\ \\ & = 7.0 \text{ kJ}\end{aligned}[/tex]
In conclusion, it will take about 7.0 × 10³ J or 7.0 kJ of energy to raise the temperature of 67 grams of water from 20 °C to 45 °C.
As part of an investigation into the strength of electrostatic forces between molecules of water, a student will measure the melting point temperature. Which part of the experimental design does this describe?(1 point)
determining the procedure
determining what data to collect
deciding on the appropriate equipment
deciding on the number of trials to perform
Which experimental design would be best to use in investigating the boiling points of water and ethanol?
Heat samples of water and ethanol in two separate beakers using a Bunsen burner. Measure the temperatures at which the samples boil using a thermometer. Record these temperatures as the boiling points.
Mix samples of water and ethanol in a beaker, then heat using a Bunsen burner. Measure the temperature at which the sample boils using a thermometer. Record this temperature as the boiling point.
Heat samples of water and ethanol in two separate beakers using a Bunsen burner. Measure the temperatures at which the samples boil using a thermometer. Conduct several trials and record the average temperatures as the boiling points.
Mix samples of water and ethanol in a beaker, then heat using a Bunsen burner. Measure the temperature at which the sample boils using a thermometer. Conduct several trials and record the average temperature as the boiling point.
Which change happens when a substance melts?(1 point)
The vibration of the molecules produces enough heat to weaken the forces of attraction between the molecules of the substance.
Heat energy overcomes the forces of attraction between the molecules of the substance, so the molecules can move more freely.
Heat energy forces the molecules of the substance farther apart until the rigid structure of the solid breaks.
The molecules of the substance move farther apart, which pulls on the intermolecular bonds between them.
Which change occurs to cause water to boil into steam?(1 point)
The addition of kinetic energy causes the motion of water molecules to overcome gravitational forces.
The addition of kinetic energy causes the motion of water molecules to overcome gravitational forces.
The removal of kinetic energy causes the motion of water molecules to overcome electrostatic forces.
The removal of thermal energy causes the motion of water molecules to overcome gravitational forces.
Answer:
1) B. determining what data to collect
2) C. Heat samples of water and ethanol in two separate beakers using a Bunsen burner. Measure the temperatures at which the samples boil using a thermometer. Conduct several trials and record the average temperatures as the boiling points.
3) B. Heat energy overcomes the forces of attraction between the molecules of the substance, so the molecules can move more freely.
4). The addition of thermal energy causes the motion of water molecules to overcome electrostatic forces.
Explanation:
I think these are the answers, i'll confirm when I finish the test.
In an experiment it is known what quantity has to measured, thus the measurement of melting point has been determining what data to collect. Thus, Option B is correct.
To investigate the boiling point of water and ethanol, the samples has to boiled at constant parameters and the data has been collected with several trials. Thus, option C is correct.
Melting has been described as the change of the solid to the liquid state. With melting, there has been heat energy higher than the force of attraction allowing the molecules to move freely. Thus, option B is correct.
The boiling has been the change in the water at liquid state to the gaseous state. With boiling there is thermal energy capable of increasing the motion of water molecules overcoming electrostatic force.
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How many carbon atoms are in 11.2 ML of C3H6O
1 mL = 0.815 g
11.2 mL = X
X = 11.2 × 0.815
= 9.128 g
mole = 9.128/58
= 0.157 mole
1 mole = 6.02 × 10^23 atoms
0.157 mol = x
X = 0.157/1 × 6.02 × 10^23
= 9.451 × 10^22 atoms of C
please to recheck answers to ensure they are correct
I really hope this helps
Which muscles is most important to you and why?
Answer:
cardiac muscle
Explanation:
because they help the heart to pump blood to all parts of the body
Answer:
Muscle is also very important to everyone because we need our muscles to survive. The HEART is the strongest muscle in our body and is always looking to get stronger. Muscles enable us to be active and exercise. Our strength comes for our muscles and how much they are used.
Explanation:
#CarryonlearningIf 3.31 moles of argon gas occupies a volume of 100 L what volume does 13.15 moles of argon occupy under the same temperature and pressure
Answer:
397 L
Explanation:
Recall the ideal gas law:
[tex]\displaystyle PV = nRT[/tex]
If temperature and pressure stays constant, we can rearrange all constant variables onto one side of the equation:
[tex]\displaystyle \frac{P}{RT} = \frac{n}{V}[/tex]
The left-hand side is simply some constant. Hence, we can write that:
[tex]\displaystyle \frac{n_1}{V_1} = \frac{n_2}{V_2}[/tex]
Substitute in known values:
[tex]\displaystyle \frac{(3.31 \text{ mol})}{(100 \text{ L})} = \frac{(13.15\text{ mol })}{V_2}[/tex]
Solving for V₂ yields:
[tex]\displaystyle V_2 = \frac{(100 \text{ L})(13.15)}{3.31} = 397 \text{ L}[/tex]
In conclusion, 13.15 moles of argon will occupy 397* L under the same temperature and pressure.
(Assuming 100 L has three significant figures.)
How many species are known to be living on Earth?
Answer:
8.7 million species
Explanation:
Scientists have estimated that there are around 8.7 million species of plants and animals in existence.
A 4.0 L balloon has a pressure of 406 kPa. When the pressure increases to 2,030 kPa, what is the volume? *
0.4 L
0.8 L
0.2 L
1 L
The new volume when pressure increases to 2,030 kPa is 0.8L
BOYLE'S LAW:
The new volume of a gas can be calculated using Boyle's law equation:
P1V1 = P2V2
Where;
P1 = initial pressure (kPa)P2 = final pressure (kPa)V1 = initial volume (L)V2 = final volume (L)According to this question, a 4.0 L balloon has a pressure of 406 kPa. When the pressure increases to 2,030 kPa, the volume is calculated as:
406 × 4 = 2030 × V2
1624 = 2030V2
V2 = 1624 ÷ 2030
V2 = 0.8L
Therefore, the new volume when pressure increases to 2,030 kPa is 0.8L.
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The N2O decomposition, 2 N2O (g) → 2 N2 (g) + O2 (g), is a zero order reaction that has a reaction rate constant of 2.00 × 10−3 M/s. Initially, 2.00 moles of N2O gas are infused into a 1.00 L vessel at 300. K.Calculate the pressure inside the vessel at 100. seconds after the start of the reaction. Temperature is held constant.
Answer:
2.00n2g
Explanation:
hope its attachments
why lysine is less basic than arginine
Answer:
Arginine is the most basic among them because it contains guanidine side group, −(CH2)4NHC(=NH)NH2, which is basic. Lysine has two amine groups, which makes it overall basic because of the second isolated amine group (−(CH2)4NH2). Histidine, on the other hand, contains imidazole group, which is also basic.
Explanation:
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What is the function of the nervous system? What is the basic unit of the nervous system?
#Nova
Answer:
The basic unit of the nervous system is a nerve cell or neuron. The nervous system transmits signals between the brain and the rest of the body, this way, the nervous system's activity controls the ability to move, breathe, see, and think.
Explanation:
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CO 2 is an element. true or false
Answer: false
Explanation:
f this helps typically an element wont have a 2 next to it, to see if something is an element or compound check for the element on the periodic table and see if the structure or name matches the one given to you on the question. for example here it is Co2 on the periodic table it's simply written as Co
co2 or carbon dioxide is a compound not an element, you can even check this on the periodic table
Answer:
true
Explanation:
co2 is carbon dioxide
Hope this helps.
Two substances both exhibit hydrogen bonding. Substance A has a boiling point of 78.4ºC. Substance B has a boiling point of 100ºC. Which statement correctly compares the substances?(1 point)
A) Substance A has stronger bonds, and it takes more energy to undergo a phase change.
B)Substance B has stronger bonds, and it takes more energy to undergo a phase change.
C) Substance B has stronger bonds, and it takes less energy to undergo a phase change.
D) Substance A has stronger bonds, and it takes less energy to undergo a phase change.
Answer:
The answer is C
Explanation:
Just took the test
Hydrogen bonding is the intermolecular interaction that occurs due to electronegativity differences. Substance B has stronger bonds and requires more energy. Thus, option B is correct.
What is hydrogen bonding?Hydrogen bonding is present in the water molecules that is because of the electronegativity differences and the dipole-dipole interaction. The hydrogen of the water molecule is bonded to the oxygen molecule.
The hydrogen bonding affects the boiling and the melting point of the substances as more energy are required to change the phase of the matter. So when substance B requires 100ºC than substance A (78.4ºC) it shows strong hydrogen bonding.
Therefore, option B. substance B has a strong hydrogen bond is correct.
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A student wants to determine the melting point of water as part of an investigation into the strength of electrostatic forces. The student considers determining the freezing point of water instead. Is this a valid option?
According to the forces of attraction freezing point and boiling point of water are different and are not related to strength of electrostatic forces.
What are forces of attraction?
Forces of attraction is a force by which atoms in a molecule combine. it is basically an attractive force in nature. It can act between an ion and an atom as well.It varies for different states of matter that is solids, liquids and gases.
The forces of attraction are maximum in solids as the molecules present in solid are tightly held while it is minimum in gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.
The physical properties such as melting point, boiling point, density are all dependent on forces of attraction which exists in the substances.
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Write the symbol for every chemical element that has atomic number less than 13 and atomic mass greater than 17.2 u.
Please help help helpppppppp
In the chemical stockroom, there is a 0.500 L bottle filled with 2.30 M CuSO4 solution. How many moles of CuSO4 are in the bottle?
A. 0.217 moles
B. 4.60 moles
C. 01.15 moles
D. 1.80 moles
The number of moles of the solute in the solution is the product of its volume and molarity. The number of moles of copper sulphate in 0.500 L of 2.30 M solution is 1.15 moles.
What is molarity?Molarity of a solution is the common term used to represent the concentration of a solution. It is the ratio of its number of moles of solute to the volume of solution in liters.
Molarity = no.of moles/volume in L.
Molarity is a temperature dependant quantity.
The given solution has a volume of 0.500 L.
molarity of copper sulphate solution = 2.30 M
Thus, number of moles of copper sulphate solute dissolved in 0.50 L of water is calculated by multiplying the volume with molarity.
No. of. moles of copper sulphate = molarity × volume
= 0.500 L × 2.30 M = 1.15 moles.
Therefore, there will be 1.15 moles of copper sulphate in the solution.
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name the main form of energy released by the reaction between hydrogen and oxygen inside a combustion engine
Answer:
When molecular hydrogen (H2) and oxygen (O2) are combined and allowed to react together, energy is released and the molecules of hydrogen and oxygen can combine to form either water or hydrogen peroxide . These two processes are represented by the two chemical equations shown at right.
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How many valence electrons are there in the molecule CH3OCH2CH3.
Answer:
There are 27 Valence electrons : )
4+1+1+1+6+4+1+1+4+1+1+1 is 27
Explanation:
There are a total of [5×1]+[2×4]+[7]=21[5×1]+[2 × 4 ] + [ 7]=21 valence electrons
ou dissolve a 2.50 g penny in 50.0 mL of HNO3. After reacting overnight, you dilute the blue solution to a volume of 100 ml. You test a sample of this solution, and find that it has an absorbance of 0.12 abs at 635 nm. i Calculate the concentration of Cu
This question is describing an spectrophotometry experiment in which the concentration of copper(II) ions has to be determined when 2.50 g of a copper-rich penny is reacted with 50.0 mL of nitric acid. In addition, the absorbance of a sample of the solution turned out to be 0.12 at 635 nm, so that the concentration was estimated as 12.8 g/L.
First of all, we must recall the Beer's law that can be written as follows:
[tex]A=ebC[/tex]
Whereas A is the absorbance of the sample, e the molar absorptivity, b the cuvette's path and C the concentration. However, this problem is not providing sufficient information to calculate the required concentration, however, similar absorbance experiments have graphed (absorbance vs concentration) calibration curves exhibiting trendlines as the one shown below:
[tex]y=0.009647x-0.003655[/tex]
Thus, since y stands for the absorbance and x for the concentration but in g/L not M (mol/L) for those experiments, we can set y equal to 0.12 so we solve for x as the concentration of the copper(II) ions in the sample:
[tex]y=0.009647x-0.003655\\\\x=\frac{0.12+0.003655}{0.009647}\\\\x=12.8g/L[/tex]
Nevertheless, it would be great if you come up with your own trendline, having clear the units for the absorbance vs concentration graph and thus double check your results because the data was not enough for the time being.
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(Beer's law and trendlines) https://brainly.com/question/5093710(Spectrophotometry) https://brainly.com/question/14467788Oxygen-15 decays through the release of a beta particle. Draw what the nucleus would look like after a beta particle is emitted. What element does it become?
When oxygen -15 nucleus undergoes beta emission, it is transformed into Fluorine - 15 nucleus.
Beta decay is said to occur when a neutron is converted to a proton. This process leads to the emission of en electron. The neutron - proton ratio decreases and the atomic number of the daughter nucleus is greater than that of the parent nucleus by one unit.
Hence, when oxygen -15 nucleus undergoes beta emission, it is transformed into Fluorine 15 nucleus.
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what percentage of oxygen is attributed fossil fuel combustion
A.43%
B.77%
C.4%
D.17%
Answer:
C. 4%
Explanation:
The answer is 4%
How many atoms of copper in 3. 11 g of copper
Hope you could get an idea from here.
Doubt clarification - use comment section.
A quantity of HCL ( 1.5*10⁻³ M) is added to water at 25°C to increase the hydrogen ion concentration from 1*10⁻⁷ to 1.5* 10⁻³ moles per liter. What is the new hydroxyl ion concentration?
The discrepancy between results given by the van der Waals equation and the ideal gas law will increase as:
This question is recalling the behavior of real gases in contrast to ideal gases, defined by the van der Waals equation and the ideal gas law respectively, and a reason behind the increasing discrepancy is required.
In such a way, we can start by considering the attached picture in which the choices are shown and clearly, the answer is "as the polarity of the molecules increase".
The aforementioned can be explained with the concept of intermolecular forces, because ideal gas theory states that ideal gas molecules do not interact one to another, and, as the polarity of the molecules increase, these intermolecular forces increase their frequency and strength, and will lead to the formation of associations, which fail to be numerically modelled by simple equations of state such as van der Waals, Redlich-Kwong, Peng-Robinson, etc,.
These associations are, of course, thoroughly neglected by the ideal gas law whereas the ones included in the van der Waals equation, which are not the most reliable, merely attempt to approach this phenomenon, which cause the mentioned discrepancy. As an additional data, robust equations of state, such as CPA (cubic plus association) are able to provide reliable results when working with highly polar gases but turn out really tough to work with due to its mathematical complexity.
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https://brainly.com/question/13423552https://brainly.com/question/13201335What volume in liters of carbon dioxide will be produced by the reaction of 18.5 liters of oxygen gas at STP?
L CO2
C3H8(g) + 5 O2(g) --> 3 CO2(g) + 4 H2O(g)
**Report your answer to the correct number of significant digits!
Answer:
0.16 L
Explanation:
Step 1: Write the balanced equation
C₃H₈(g) + 5 O₂(g) → 3 CO₂(g) + 4 H₂O(g)
Step 2: Calculate the moles of CO₂ produced from 0.012 moles of O₂
The molar ratio of O₂ to CO₂ is 5:3. The moles of CO₂ produced are 3/5 × 0.012 mol = 0.0072 mol.
Step 3: Calculate the volume occupied by 0.0072 moles of CO₂ at standard temperature and pressure
At STP, 1 mole of CO₂ occupies 22.4 L.
0.0072 mol × 22.4 L/1 mol = 0.16 L
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Serena mixed two samples together: a gray solid that smells like flowers and a gray solid that smells like bleach. She analyzed the results and found two ending substances. One of the ending substances was a white solid. This ending substance is made up of the repeating group of atoms shown above. Which of the diagrams to the left shows the repeating groups of atoms that make up the samples Serena mixed together?
The diagrams that shows the repeating groups of atoms that make up the samples which were mixed together is option D.
A chemical reaction is said to have occurred when there a rearrangement of atoms in a substance. This rearrangement of atoms in the substance leads to the formation of new substances.
In this case, we must note that the combination of reactants to be chosen must posses the atoms shown as part of the one of the end substance. The only option that satisfies this requirement is option D.
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Answer:D
Explanation:DDDDD
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Answer:
An unbalanced force causes the object to change position.
Explanation:
An unbalanced force causes the object on which it is acting to accelerate, changing its position, speed, or direction due to equal forces on opposite sides.
According to Dalton's atomic theory, atoms
a: of different elements combine in simple whole-number ratios to form compounds
b: can be divided into protons, neutrons, and electrons
c: of all elements are identical in size and mass
d: can be destroyed in chemical reactions
According to Dalton's atomic theory, atoms of different elements combine in simple whole-number ratios to form compounds.
DALTON'S ATOMIC THEORY:As the name implies, Dalton's atomic theory is a theory proposed by an English scientist named John Dalton in the 1900's.
The Dalton's atomic theory is composed of five main parts, which are as follows:
All matter is comprised of tiny, definite particles called atoms.Atoms are indivisible and cannot be destroyed.All atoms of a particular element are identical in size and weight.Atoms of different elements contain different mass.Atoms of different elements combine in fixed whole-number ratios when forming compounds.Therefore, in accordance to Dalton's atomic theory, atoms of different elements combine in simple whole-number ratios to form compounds.
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Ionic bond occurs between two atoms that have different:
a) Electron
b)Size
c)Polarity
d)Energy
e)Charge
Answer:
Ionic bond occurs between two atoms that have different:
a) Electron
Explanation:
according to the definition of ionic bond,
it is the electrostatic force of attraction that holds the two oppositely charged ions together and an ionic bond or electrovalent bond is formed when one atom gains electrons while the other atom loses electrons from its outermost level or orbit.
why do we need to study thermodynamics?