Answer:
involve the transfer of energy
Explanation:
in endothermic requires the input of energy whereas in exothermic it release energy upon completion.
What is the mass number of an atom that has 19 protons, 19 electrons, and 20 neutrons?
Answer:
[tex]\boxed {\boxed {\sf 39}}[/tex]
Explanation:
The mass number of an atom can be found by adding the number of protons and neutrons.
[tex]mass \ number =protons + neutrons[/tex]
There are 19 protons and 20 neutrons.
[tex]protons=19 \\neutrons=20[/tex]
[tex]mass \ number= 19+20[/tex]
[tex]mass \ number =39[/tex]
The mass number of this atom is 39
A student has a balloon with a volume of 2.5 liters that contains 4.0 moles of air. The ballon has a small leak, allowing one mole to escape, leaving just 3.0 moles of air inside the balloon. What is the balloon's new volume after the air has escaped?
Answer:
1.9 L
Explanation:
Step 1: Given data
Initial number of moles of air (n₁): 4.0 molInitial volume of the balloon (V₁): 2.5 LFinal number of moles of air (n₂): 3.0 molFinal volume of the balloon (V₂): ?Step 2: Calculate the final volume of the balloon
According to Avogadro's law, the volume of an ideal gas is directly proportional to the number of moles. We can calculate the final volume of the balloon using the following expression.
V₁ / n₁ = V₂ / n₂
V₂ = V₁ × n₂ / n₁
V₂ = 2.5 L × 3.0 mol / 4.0 mol
V₂ = 1.9 L
According to VSEPR theory, a molecule with the general formula AX4 E1 will have a __________ molecular shape.a. T-shaped square planar b. seesaw c. trigonal planar d. trigonal bipyramidal e. tetrahedral
Answer:
The answer is "Option e"
Explanation:
The ionic bond arousal system of the outer shells (VSEPR) allows us to determine which one of the feasible solutions are found in the majority of instances. It's also supposed to occupy the space with electrical pairs and also to reduce electrical couple repulsive forces to a minimum, its cheapest electricity framework. This theory can be used for predicting a form of electron pairs with a different mass of a particle's core electrons.
Assume a density of water of 1.00 g/mL, and calculate the mass of water in the solution
Answer:
1g or 10^-3kg
Explanation:
as you know , the density =mass \volume
so you have the mass from the number it self
[tex]\frac{1g}{1 ml}[/tex] so from this equation, you will get 1 g and you can to SI to be [tex]10^{-3}[/tex]kgA child is prescribed morphine sulfate at 35.0 mcg/kg/dose. The child weighs 85 lb and the solution is available as a 5.0-mg/mL vial. How many milliliters should be injected?
Answer:
270 mL
Explanation:
First we convert the child's weight to kg:
85 lb * [tex]\frac{453.592g}{1 lb} *\frac{1kg}{1000g}[/tex] = 38.56 kgSo the total mass of morphine sulfate that should be injected is:
38.56 kg * 35.0 mg/kg/dose = 1349.6 mg/doseFinally we calculate the volume that should be injected, using the concentration of the available solution:
1349.6 mg ÷ 5.0 mg/mL = 269.9 ≅ 270 mLThe accurate millilitre is 268 mL.
First of all, we must obtain the mass of the child in kilograms;
1 Ib = 0.45 Kg
85 lb = 85 lb × 0.45 Kg/1 Ib
= 38.25 Kg
If 1 Kg takes 35.0 mcg/kg/dose
38.25 Kg takes 38.25 Kg × 35.0 mcg/kg/dose/1 Kg
= 1338.75 mg/dose
Hence;
1338.75 mg/dose/5.0-mg/mL = 268 mL
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If element X has 6 valence electrons, what is the formula between element X and
magnesium.
a. X6Mg2
b. MgX3
c. MgX
d. XMg
how many sodium ions are in 1.4 kg of sodium chloride, NaCl?
Answer:
1.44 x 10²⁵ ions of Na⁺
Explanation:
Given parameters:
Mass of NaCl = 1.4kg = 1400g
Unknown:
Number of ions of sodium = ?
Solution:
The compound NaCl in ionic form can be written as;
NaCl → Na⁺ + Cl⁻
In 1 mole of NaCl we have 1 mole of sodium ions
Now, let us find the number of moles in NaCl;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
Number of moles = [tex]\frac{1400}{58.5}[/tex] = 23.93mol
So;
Since 1 mole of NaCl gives 1 mole of Na⁺
In 23.93 mole of NaCl will give 23.93 mole of Na⁺
1 mole of a substance = 6.02 x 10²³ ions of a substance
23.93 mole of a substance = 6.02 x 10²³ x 23.93
= 1.44 x 10²⁵ ions of Na⁺
I need help with this, please I need it ASAP
It's science, ignore that it says Chemistry. There was no science
10. For each of the following pairs of ionic compounds, state which would be expected to have the higher (more negative) lattice energy.
a. LiF or KBr
b. NaCl or MgS
c. MgO or RbI
Answer:
C I belive
Explanation:
The higher lattice energy in option a is for LiF. Similarly, MgS have higher lattice energy that NaCl and MgO have higher lattice energy than RbI.
What is lattice energy?Lattice energy of a compound is the energy required to convert one mole of that compound into its constituent gaseous ions. Lattice energy increases as the size of the ion decreases. As well as, higher the charge of the ions higher will be the lattice energy.
In LiF and KBr, Li and F are the smaller ions and is having higher lattice energy. In the case of NaCl and MgS, Mg and S are having +2 charge and are smaller causes MgO higher in lattice energy.
Similarly in the case of MgO and RbI the same concept can be applied. Rb⁺ and I⁻ are bigger ions where as Mg²⁺ and O²⁻ are comparatively smaller and have higher charge result in higher lattice energy.
Thus compound which have higher lattice energy in option a is LiF, in option b is MgS and in option C is MgO.
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What does this passage explain about people?
why mothers favor some children over others
the contrasting sides of human nature
why there is harmony in all things
left- and right-handedness
Answer:
the contrasting sides of human nature
Explanation:
I took the test
what reacts at room temperature with ethanol and also with ethanoic acid
Answer: Its esterification reaction.
when organic acid react with alcohol it forms ester and water. reaction is known as esterification reaction.
CH3COOH + C2H5OH → CH3COOC2H5 + H2O
ethanoic acid + ethanol → ethyl acetate + water
this reaction takes place in the presence of acid catalyst ( dil H2SO4).
in this reaction oxygen of ethanol with lone pair act as nucleophile and carbonyl carbon of acetic acid act as electrophile.. so its nucleophilic substitution reaction of -COOH group.
Explanation:
A scientist performs an experiment involving the collision of two masses on a flat surface. She believes she has made a startling discovery: the total kinetic energy is not conserved. What might she have overlooked?
A.
Some gravitational potential energy may have been gained.
B.
Some gravitational potential energy may have been lost.
C.
Some energy may have been gained due to friction and/or sound.
D.
Some energy may have been lost due to friction and/or sound.
Answer:
c
Explanation:
How are protons, neutrons, and electrons arranged to form an atom?
Answer:
Protons are in the middle, electrons are on the loop (outside area) and the neutrons are mixed with the protons.
Explanation:
Answer:
The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge). Atoms are made up of protons and neutrons located within the nucleus, with electrons in orbitals surrounding the nucleus.
Explanation:
Fossil fuels contribute to about 85% of the total energy produced in the world. What is a direct environmental
consequence of the extensive use of fossil fuels?
Answer:your a poop face
Explanation:
Imagine not knowing the answer
Answer: C
Explanation:
20. What part of an atom exists in orbitals surrounding the nucleus?
A. electron
B. photon
C. neutron
D. proton
Titration of a strong acid with a strong base. The pH curve for titration of 50.0 mL of a 0.100 M solution of hydrochloric acid with a 0.100 M solution of NaOH(aq). What volume of NaOH(aq) would be needed to reach the equivalence point if the concentration of the added base were 0.240 M?
Answer:
Explanation:
we know that M1V1=M2V2
M1=0.100 M
V1=50.0*10^-3 L
M2=0.100 M
V2=M1V1/M2
V2=0.100*50.0*10^-3/0.100
V2=0.05
To know the end point we use phenolphthalein as indicator. End point is a point where completion of reaction happen. The volume of NaOH needed to reach the equivalence point if the concentration of the added base were 0.240 M is 20.8ml.
What is titration?Titration is a technique by which we know the concentration of unknown solution using titration of this solution with solution whose concentration is known.
The balanced equation is
HCl+NaOH[tex]\rightarrow[/tex]NaCl+H₂O
Using following equation
M₁×V₁=M₂×V₂
Where,
M₁=molarity of HCl= 0.100 M
V₁=volume of HCl=50.0 mL
M₂=molarity of NaOH=0.240 M
V₂=volume of NaOH=?
Substituting the given values
0.100 M ×50.0 mL=0.240 M×V₂
V₂=20.8ml
Therefore, the volume of NaOH needed to reach the equivalence point if the concentration of the added base were 0.240 M is 20.8ml.
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defferent between crysttiline solid and amerphus solid
Answer:
Crystalline solids have well-defined edges and faces, diffract x-rays, and tend to have sharp melting points. In contrast, amorphous solids have irregular or curved surfaces, do not give well-resolved x-ray diffraction patterns, and melt over a wide range of temperatures.
Explanation:
Hope this helped!
Answer:
Crystalline solids have well-defined edges and faces, diffract x-rays, and tend to have sharp melting points. In contrast, amorphous solids have irregular or curved surfaces, do not give well-resolved x-ray diffraction patterns, and melt over a wide range of temperatures.
Explanation:
What is the answer? Please
What energy is required for a reaction to occur?
A. Bond energy
B. Activation energy
C. Kinetic energy
D. Potential energy
Answer:
B. Activation Energy
Explanation: A P E X
Answer: the answer is activation energy
Explanation:
i just took the test
How many moles of KCI would be dissolved in 4 L of water to make a 2 M
solution?
1
A.
mole
B. 2 moles
C. 8 moles
D. 4 moles
Answer:
C. 8 Moles
Explanation:
A collection of the same kind of cells working together to do the same job
Answer:
A group of cells doing the same job forms a tissue. A group of tissues working together forms an organ. Organs work in groups, too. A group of organs doing the same job is called a system.
Explanation:
What happened to solid materials when mixed with the liquid materials?
Answer:
the solid materials will disappear after mixing with a liquid material
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Answer: go fk your dad you fkin whor
What do chemical compounds want to obey?
Answer:
Their atoms obey the octet rule
Explanation:
Chemical compounds are formed when atoms combine with one another in order to comply with the octet rule. The octet configuration gives an atom stability in electronic structure.
When atoms become isoelectronic with noble gases, it confers a special stability on them. Therefore, to attain this state, they gain or lose electron or share their electrons with other species.H20+ SO3 ? Which compound is likely produced by the chemical reaction?
Answer:
h2so4
Explanation:
im big brain.
Calculate how many grams of sodium hypochlorite can be theoretically formed when 1.23 mol of sodium hydroxide is combined with 1.36 mol of chlorine.
Answer:
45.78 g NaClO
Explanation:
The reaction that takes place is:
2NaOH + Cl₂ → NaCl + NaClO + H₂OIn order to react completely, 1.36 moles of chlorine would require (2*1.36) 2.72 moles of NaOH. There are more moles than that, so NaOH is the limiting reactant.
We calculate the moles of NaClO formed, from the limiting reactant:
1.23 mol NaOH * [tex]\frac{1molNaClO}{2molNaOH}[/tex] = 0.615 mol NaClOFinally we convert NaClO moles to grams, using its molecular weight:
0.615 mol NaClO * 74.44 g/mol = 45.78 g NaClOa sample gas is in the rigid cylinder with a movable piston the pressure of the gas is kept constant if the kelvin temperature of the gas is doubled the volume of the gas is?
Answer:
The pressure of the gas is kept constant. If the Kelvin temperature of the gas is doubled, the volume of the gas is. O 1.
2. A person with a body temperature of 37°C holds an ice cube with a temperature of 0°C
in a room where the air temperature is 20°C. The direction of heat flow is
a) From the person to the ice, only
b) From the person to the ice and air, and from the air to the ice
c) From the ice to the person, only
d) From the ice to the person and air, and from the air to the person
Answer:
b) From the person to the ice, and from the air to the ice
Explanation:
The direction of heat flow in the room is from the person to the ice and from the air to the ice.
The ice is at the lowest temperature.
Heat flows from a place with a higher measure of heat to a place with a lower amount of heat. Since the ice has the lowest heat, there is a thermal gradient set up. Heat will flow from the body and air towards to the ice.Toluene is subjected to the action of the following reagents in the order given: (1) KMnO4,OH-, heat; then H3O (2) HNO3, H2SO4 (3) Br2, FeBr3 What is the final product of this sequence?
Answer:
See image attached
Explanation:
The reaction of toluene with alkaline potassium permanganate in the presence of heat leads to the oxidation of the -CH3 to give benzoic acid.
Reaction benzoic acid with HNO3/H2SO4 yields the nitronium ion (NO2+).
Recall that -COOH is a metal director and deactivated the ring towards electrophilic substitution hence the m-nitrobenzoic acid is formed.
Reaction with FeBr3/Br2 yields the product shown in the image attached.
Can you answer these two questions right please and thank you
Answer:
B. LZAQD
A. Younger than A but older than Q
Explanation:
To solve this problem, we simply apply the stratigraphic laws which are the law of superposition and principle of cross cutting.
According to the law of superposition, in an undeformed sequence of strata, the oldest layer is always at the bottom and the youngest on top. In this case, we have a little disturbance but it did not affect much of the original bedding. So, the rock ages from L to Z to A to Q and D. L is the oldest and D is the youngest.According to the principle of cross-cutting "features that cuts through a rock are younger than the layers they cut through". In this problem, the fault cuts through layers LZ and A which suggests that these layers are older than the faulting event. Layer Q is unaffected by the faulting so, the fault is older than the layer.
Complete the balanced molecular chemical equation for the reaction below.
If no reaction occurs, write NR after the reaction arrow.
Cu2SO4(aq) + Li3PO4(aq)
Answer:
Following are the complete balance of the given equation:
Explanation:
Given equation:
[tex]Cu_2SO_4(aq) + Li_3PO_4(aq)[/tex]
[tex]Cu_2So4\ (aq)+Li_3Po_4 \(aq) \longrightarrow Cu_3(Po_4)\ (aq)+Li_2So_4 \ (aq)[/tex]
After Balancing the equation:
[tex]3 Cu_2So4\ (aq)+ 2 Li_3Po_4\ (aq) \longrightarrow 2 Cu_3(Po_4)\ (aq)+ 3Li_2So_4 \ (aq)[/tex]
In the above equation, when the 3 mol Copper sulfate reacts with 2 mol lithium phosphate , it will produce 2 mol Copper phosphate and 3 mol Lithium sulfate .