Answer:
enthalpy of fusion also called heat of fusion
#1 - What is a pure substance? *
1 point
two or more atoms held together by chemical bonds
the attractive force that holds atoms together
a sample of matter that has specific chemical and physical properties
a pure substance made up of two or more different types of atoms joined by chemical bonds
#2 - TRUE OF FALSE: Water is a pure substance.
1 point
True
False
#3 - What is an atom? *
1 point
the smallest unit of an element that keeps the properties of that element
the attractive force that holds atoms together
a sample of matter that has specific chemical and physical properties
a pure substance made up of two or more different types of atoms joined by chemical bonds
#4 - What is a molecule? *
1 point
two or more atoms held together by chemical bonds
the attractive force that holds atoms together
a sample of matter that has specific chemical and physical properties
a pure substance made up of two or more different types of atoms joined by chemical bonds
#5 - What is a chemical bond? *
1 point
two or more atoms held together by chemical bonds
the attractive force that holds atoms together
a sample of matter that has specific chemical and physical properties
a pure substance made up of two or more different types of atoms joined by chemical bonds
#6 - TRUE OR FALSE: Molecules are all the same size. *
1 point
True
False
#7 - What is a compound? *
1 point
two or more atoms held together by chemical bonds
the attractive force that holds atoms together
a sample of matter that has specific chemical and physical properties
a pure substance made up of two or more different types of atoms joined by chemical bonds
#8 - TRUE OR FALSE: Compounds never form in a fixed ratio. *
1 point
True
False
#9 - TRUE OR FALSE: The structure of matter at the atomic and molecular levels is too small to observe directly. *
1 point
True
False
#10 - TRUE OR FALSE: A complex molecule may contain a few atoms bonded together. A simple molecule may contain thousands of atoms. *
1 point
True
False
#11 - What is a crystal? *
1 point
two or more atoms held together by chemical bonds
a substance in which the particles are arranged in an orderly, geometric, and repeating pattern
a sample of matter that has specific chemical and physical properties
a pure substance made up of two or more different types of atoms joined by chemical bonds
#12 - TRUE OR FALSE: Diamond and graphite are both made of carbon atoms. *
1 point
True
False
Answer/Explanation:
#1 - A pure substance is either an element or a compound, making it different from a mixture. A sample of matter that has specific chemical and physical properties is the only one that fits here.
#2 - A pure substance is either an element or a compound, making it different from a mixture. Water is a compound, and thus this would be true.
#3 - An atom is the smallest unit of an element that keeps the properties of that element. Just refer to its definition.
#4 - A molecule is two or more atoms held together by chemical bonds . Again, just refer to its definition.
#5 - A chemical bond is the attractive force that holds atoms together . Jus refer to its definition.
#6 - Molecules are most definitely not all the same size, especially given the huge number of them. This would be false.
#7 - A compound is a pure substance made up of two or more different types of atoms joined by chemical bonds . Just refer to its definition.
#8 - Compounds always form in a fixed ratio, so this would be false.
#9 - If by directly, the problem means with the naked eye, this would be true.
#10 - False. It's reversed.
#11 - A crystal is a substance in which the particles are arranged in an orderly, geometric, and repeating pattern . Just refer to its definition.
#12 -True; to be more specific, they are covalent network solids.
(4.2 x 10^8) + (2.6 x 10^6) *
Answer:
4.226×10^8
Explanation:
4.2 ×10^8+2.6×10^6=422600000
or 4.226×10^8
How much energy is required to melt 2 kg of copper? Use the table below and
this equation: Q = mLfusion:
414 kJ energy is required to melt 2 kg of copper. Hence, option B is correct.
What is energy?Energy is the capacity for doing work.
Given parameters:
Mass of copper = 2kg
Unknown:
Amount of energy required to melt the copper =?
Solution:
To solve this problem, we use:
Q = m L
m is the mass
L is the latent heat of fusion of copper = 207kJ/kg
So;
Q = 2 x 207 = 414kJ
Hence, option B is correct.
Learn more about energy here:
https://brainly.com/question/1932868
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what kind of change forms a chemical reaction?
a. a phase change
b. a solubility change
c.a physical change
d. a chemical change
Answer:
a chemical change is correct answer
workout the oxidation number of phosphorus in the following compound H3PO3
Answer:Phosphorus ahs an ocxidation number of 3. Phosphoric acid, H3PO3 has structure where there is one hydrogen (-H), two hydroxyl groups (-OH) and one oxgen (=O) attached to the central phosphorus P
Using the normal rules, H= +1, O = -2, OH = -1 and balancing out the "charges" we get P =+3
Explanation:
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X-rays had a frequency of about 3x10^18 determine it's wavelength (in nm) and energy per photon
Answer:
λ = 0.1 nm
E = 2 × 10⁻¹⁵ J
Explanation:
Step 1: Given data
Frequency of X-rays (ν): 3 × 10¹⁸ s⁻¹
Step 2: Calculate the wavelength (λ) of a photon of X-rays
We will use the following expression.
c = λ × ν
where,
c: speed of light
λ = c / ν
λ = (3.00 × 10⁸ m/s) / 3 × 10¹⁸ s⁻¹
λ = 1 × 10⁻¹⁰ m × (10⁹ nm/1 m) = 0.1 nm
Step 3: Calculate the energy (E) of a photon of X-rays
We will use the following expression.
E = h × ν
where,
h: Planck's constant
E = 6.63 × 10⁻³⁴ J.s × 3 × 10¹⁸ s⁻¹
E = 2 × 10⁻¹⁵ J
Can someone help me
Answer:
The longer it takes to orbit the sun.
Explanation:
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Answer:
In all of the ecoregions, wind and rain can weather and erode the landforms and soil. Rivers are also
powerful weathering and erosion agents. They can cut into rock and form canyons. When rivers deposit
eroded material, they change their shape or extend the shoreline. When waves along coastlines deposit
sediment, they extend beaches; when they wash sediment away, the waves erode beaches. Rivers, rock
formations, soils, topography, and precipitation in an ecoregion will determine how the processes of
weathering, erosion, and deposition work to reshape it.
Explanation:
A self-contained system within a larger system? *
Answer:
subsystems.
Explanation:
A self-contained system within a larger system. system. A group of interacting or interdependent elements forming a complex whole, as in all the factors or variables in an environment or all the variables that might affect a science experiment.
how many molecules of water are found in 1.5mol of water ?
Answer:
9.033×10^23 Molecules
Explanation:
We are given,
No.of moles of water = 1.5 moles
The approximate value of Avagadro's Constant =6.022×10^23 particles
Hence,
As we know that,
No.of particles = No.of moles × Avagadro's Constant
Here,
No. Of Water Molecules in 1.5 moles of water = 1.5×6.022×10^23
No.of Water Molecules in 1.5 molesof water=9.033×10^23 Molecules
Why is Newton's first law of motion important to science?
Answer:
Newton's laws are very important because they tie into almost everything we see in everyday life. These laws tell us exactly how things move or sit still, like why you don't float out of bed or fall through the floor of your house.
Explanation: Newton's laws of motion are important because they are the foundation of classical mechanics, one of the main branches of physics. Mechanics is the study of how objects move or do not move when forces act upon them.
. A certain quantity of electricity is passed through an aqueous
solution of AgNO3 and cupric salt solution connected in series. The
amount of silver deposited is 1.08 g. What is the amount of copper
deposited ? (Atomic wt. of Cu=63.54, Ag=108 g/mole).
Answer:
0.32 g
Explanation:
First, we find the number of moles n of silver deposited.
n = m/M where m = mass of silver deposited = 1.08 g and M = Atomic weight of silver = 108 g/mol
n = m/M = 1.08 g/108 g/mol = 0.01 mol
Now, the quantity of electricity Q = nF where n = number of moles of silver = 0.01 mol and F = Faraday's constant = 96500 C/mol
Q= nF = 0.01 mol × 96500 C/mol = 965 C
By the chemical equation for copper,
Cu²⁺ + 2e ⇒ Cu
2 moles of electrons deposits 1 mol of copper, that is
2 × 96500 C deposits 1 mol of copper, then 965 C will deposit x mol
x = 1 mol × 965 C/2 × 96500 C = 1/200 mol = 0.005 mol of copper
So, we find the mass of 0.005 mol of copper using
n = m/M where m = mass of copper deposited = unknown and M = Atomic weight of copper = 63.54 g/mol and n = number of moles of copper = 0.005 mol
m = nM
= 0.005 mol × 63.54 g/mol
= 0.32 g
How many grams are in 1.5moles of calcium
Answer: 60.117 g
Explanation: [tex]1.5 mol Ca = \frac{40.078g/mol}{1mol}[/tex] multiply and quit all "mol" and you get the grams
An aerosol can contains 400.0 ml of compressed gas at 5.2 atm pressure. When the gas is sprayed into a large plastic bag, the bag inflates to a a volume of 2.14 L. What is the pressure of gas inside the plastic bag?
Answer:
0.97 atm ≅ 1 atm
Explanation:
The relation between the pressure (P) and volume (V) of a gas is given by the Boyle's law. According to this, the volume is inversely proportional to the pressure:
P₁ x V₁ = P₂ x V₂
From the problem, we have:
V₁= 400.0 mL x 1 L/1000 mL = 0.4 L
P₁= 5.2 atm
V₂= 2.14 L
We calculate the final pressure (P₂) from the equation, as follows:
P₂ = (P₁ x V₁)/V₂ = (5.2 atm x 0.40 L)/ 2.14 L = 0.97 atm ≅ 1 atm
Therefore, as the volume is increased (from 0.4 L to 2.14 L), the pressure in decreased (from 5.2 atm to 0.97 atm).
A 400.0-mL can contains compressed gas at 5.2 atm. The gas is sprayed into a bag, that inflates to 2.14 L at 0.97 atm.
What does Boyle's law state?Boyle's law states that the pressure of a given mass of an ideal gas is inversely proportional to its volume at a constant temperature.
A 400.0-mL can contains compressed gas at 5.2 atm. The gas is sprayed into a bag, that inflates to 2.14 L. We can calculate the final pressure of the gas using Boyle's law.
P₁ × V₁ = P₂ × V₂
P₂ = P₁ × V₁ / V₂
P₂ = 5.2 atm × 0.4000 L / 2.14 L = 0.97 atm
where,
P₁ and V₁ are the initial pressure and volume.P₂ and V₂ are the final pressure and volume.A 400.0-mL can contains compressed gas at 5.2 atm. The gas is sprayed into a bag, that inflates to 2.14 L at 0.97 atm.
Learn more about Boyle's law here: https://brainly.com/question/469270
Compared to the valence electrons of a nonmetallic atom, the valence electrons of a metallic atom are generally A) greater in number and less strongly held B) fewer in number and less strongly held C) fewer in number and more strongly held D) greater in number and more strongly held
Answer:
B) fewer in number and less strongly held
Explanation:
If we look closely at the periodic table from left to right, we will notice that the number of valence electrons increases steadily as we move across the periodic table from left to right.
Metals are mostly at the left hand side of the periodic table while nonmetals are found at the righthand side of the table.
Metals are less electronegative than nonmetals and typically have a lower effective nuclear charge than nonmetals hence the fewer valence electrons of metals are less strongly held(due to less effective nuclear charge) than those of nonmetals.
22
Silicon(IV) oxide is a covalently bonded compound.
Which statements are correct?
1
2
Silicon atoms form four single bonds in silicon(IV) oxide.
Oxygen atoms form two double bonds in silicon(IV) oxide.
Silicon(IV) oxide has a high melting point.
Silicon(IV) oxide contains one silicon atom and four oxygen atoms.
3
4
с
D
2 and 3 only
3 and 4 only
B
1 and 3 only
1 and 2 only
А
А
Answer:
2 and 3 only
Explanation:
The formular for the compound; Silicon(IV)oxide is SO2
1. Silicon atoms form four single bonds in silicon(IV) oxide.
This statement is wrong because the silicon is doubly bonded to two oxygen atoms.
2. Oxygen atoms form two double bonds in silicon(IV) oxide.
This statement is correct.
3. Silicon(IV) oxide has a high melting point.
This statement is correct Due to it's macromolecular structure, it is able to form thousands of covalent bonds between it's sulphur and oxygen sub units.
4. Silicon(IV) oxide contains one silicon atom and four oxygen atoms.
This statement is wrong as silicon(iv) oxide contains only two oxygen atoms.
what is a metorlogist
an expert in or student of meteorology; a weather forecaster.
Mike mixes two chemicals in a container. The container quickly becomes
very hot
What can be said about this reaction?
Answer:
it is an exothermic reaction
How does heat from the sun turn liquid water into gas called water vapor?
Answer:
Explanation:Once energy is added to water by heat from the sun, the bonds between the water molecules gain kinetic energy or energy in motion. Then they escape the surface of the liquid and become a gas (water vapor), which rises into atmosphere.
5) Determine the mass if lithium hydroxide that is produced when 12.87 g of lithium nitride reacts with
an excess of water according to the following process:
Li,N + 3 H2O + 3 LiOH + NH,
Answer:
Mass = 26.58 g
Explanation:
Given data:
Mass of lithium nitride = 12.87 g
Mass of lithium hydroxide produces = ?
Solution:
Chemical equation:
Li₃N + 3H₂O → 3LiOH + NH₃
Number of moles of of Li₃N:
Number of moles = mass/molar mass
Number of moles = 12.87 g/ 34.83 /mol
Number of moles = 0.37 mol
now we will compare the moles of lithium nitride with lithium hydroxide.
Li₃N : LiOH
1 : 3
0.37 : 3/1×0.37 = 1.11 mol
Mass of LiOH:
Mass = number of moles × molar mass
Mass = 1.11 mol × 23.95 g/mol
Mass = 26.58 g
On the graph, which dimension would be changed if the rate of reaction were to be altered by a catalyst?
Answer:
The alteration of the rate of the chemical reaction by the addition of a catalyst will change the dimension of L
Explanation:
The parts of the Energy profile of a reaction diagram the given letters represent are;
K = The energy possessed by the reactants
L = Activation energy required for the reaction to take place
M = Energy threshold required for the reaction to take place
N = The change in the enthalpy from the reactants to the products, which is also the energy released
O = The energy possessed by the products
The addition of a catalyst changes the route with which the reaction takes place such that the reaction rate is increased because the activation energy, L, is reduced.
Therefore, the dimension that will be changed if the rate of reaction were to be altered by a catalyst is L.
how many moles of tin are there in 50 g of tin (II) oxide
Answer:
Moles of tin = 0.37 mol
Explanation:
Given data:
Mass of tin oxide = 50 g
Moles of tin = ?
Solution:
Number of moles of SnO:
Number of moles = mass/molar mass
Number of moles = 50 g/ 134.71 g/mol
Number of moles = 0.37 mol
We can see there is only one mole of Sn is present in one mole of tin oxide.
Thus in 0.37 mol of tin oxide,
0.37 mol × 1 = 0.37 mol of tin
Help me plz I don’t know what it’s mean
Answer:
1 has the highest density because it has the most amount of circles in the least amount of space- it is the most densely filled with circles; it is the most dense.
Answer:
image 1 would have the highest density
Explanation:
the closer the molecules are the more solid an object is. if the molecules are far apart and rarely bump into eachother, it is more gaseous. the object in the middle (2) is a liquid
how many molecules of H3PO4 are in 125 g of H3PO4
Answer:
2.11 * 10^3 molecules of phosphoric acid
Explanation:
The center atom of the CO 2 molecule corresponds to the notation
Answer:
simplest explanation regarding CO2 Molecular Geometry and hybridization. ... Carbon is the least electronegative that means it stays at the center
Explanation:
hope this helps
Which of these is an example of a hypothesis?
Add different kinds of soil to three potted plants.
Observe fish swimming up a stream.
Temperature changes may be due to wind patterns.
Wonder why some layers of rocks contain fossils.
Stop telling people how you feel they do not wanna hear you're problems tell them to God man these people don't care what you gotta say I just had to tell y'all this and write it in a notebook please I'm tryna tell y'all that's the key kings and queens stay humble 2021 is the new year and new u
Answer:
Preach!
Explanation:
1.Identify the types of bonds between the carbon and the two oxogen molecules in the carbon dioxide molecule
2.then describe the bond angle
3. Explain how the structural formula can be used to determine bond angles .
People with diabetes have to monitor and restrict their sugar intake. What volume of apple juice could
a diabetic person drink, if the person's sugar allowance for that beverage was 8.0 g? Assume that the
apple juice has a sugar concentration of 8.0 % w/v.
The volume of apple juice could a diabetic person drink : 100 ml
Further explanationGiven
sugar allowance = 8 g
sugar concentration of apple juice : 8.0% w/v
Required
Volume of apple juice
Solution
The concentration of a substance can be expressed in several quantities The concentration shows the amount of solute in a unit of the amount of solvent.
% w/v = mass of solute (weight) in g / 100 ml solution
So for 8% w/v = 8 g of sugar(solute) in 100 ml of apple juice