Answer:
q = mC∆T
q = heat = ?
m = mass = 6.30 g
C = specific heat = 0.385 J/g/deg
∆T = change in temperature = 32-20 = 12º
q = ((6.30 g)(0.385 J/g/deg)(12 deg) = 29.1 J (to 3 significant figures)
Explanation:
4.0 g of sodium hydroxide NaOH was dissolved in sufficient water to make up 125 mL of solution.
A) Find the concentration of the solution.
B) What mass of sodium hydroxide could be obtained by heating a 20 mL sample of this solution to dryness?
C) If 30 mL of the solution were mixed with sufficient water to produce 480 mL of a more dilute solution, what would be the concentration of the dilute solution?
D) If 200 mL of the more dilute solution were then mixed with 100 mL of the more concentrated solution, what would be the concentration of the mixed solution?
Answer:
(A) 0.80 M
(B) 0.64 g
(C) 0.050 M
(D) 1.6 M
Explanation:
(A)
Convert 4.0 g to moles with molar mass. Convert 125 mL to L.
4.0 g x (1 mol/39.998 g) = 0.100 mol
125 mL x (1 L/1000 mL) = 0.125 L
Molarity = mol/L
Molarity = 0.100 mol/0.125 L = 0.80 M
(B)
Find moles of NaOH with the molarity you just found. And convert 20 mL to L.
Molarity = mol/L
0.80 M = mol/0.020 L
mol = 0.016
Convert moles to grams with molar mass.
0.016 mol x (39.998 g/1 mol) = 0.64 g
(C)
You know the molarity of a NaOH solution (Part A). 30 mL initial volume and 480 mL final volume are given. Dilution question so use the dilution formula.
M1V1 = M2V2
(0.80 M)(30 mL) = (M2)(480 mL)
M2 = 0.050 M
(D)
Dilution question again, use the dilution formula.
M1V1 = M2V2
(0.80 M)(200 mL) = (M2)(100 mL)
M2 = 1.6 M
Help me plss correct answer
Answer:
The answer is for your question is A
5 The atoms of a certain element each contain 36 protons and 8 valence electrons. Which
statement correctly identifies this element and describes its chemical reactivity? (8.58)
A The element is krypton, Kr, and it is not very reactive.
B The element is chlorine, Cl, and it is highly reactive.
C The element is krypton, Kr, and it is highly reactive.
D The element is chlorine, Cl, and it is not very reactive.
Answer:
dfdfaxc b
Explanation:
. I am described as being conductive, malleable, shiny, and reactive with HCl. I am one of the most reactive elements. I turn black within seconds when I am exposed to air. If someone drops water on me, I will explode. When I do explode I send off characteristic purple-red (violet) flame. Who am I?
Answer:
Potassium
Explanation:
Most reactive metal in the reactivity series
The element in the question is referred to the alkali metal which is known as Potassium
Potassium is a highly reactive metal and reacts with Hydrochloric acid to
form a salt known as Potassium chloride and hydrogen gas.
Hcl + K ⇒ Kcl₍s₎ + H₂₍g₎
Potassium has a white color but when it reacts with water it explodes and
gives out a purple-red color as a result of the high excitation of electrons.
Read more on https://brainly.com/question/22993452
Given the balanced reaction: 2KOH + H2SO4 → 2H20 + K2SO4
What mass of KOH is required to react completely with 2.70 grams of
H2SO4 to produce K2SO4 and water?
Molar mass of H2SO4 is 98 grams.
Molar mass of KOH is 56 grams.
O 2.36 g
O 3.09 g
4.73 g
O 1.54 g
I will give brainliest
Answer: 3.09 g
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} H_2SO_4=\frac{2.70g}{98g/mol}=0.0275moles[/tex]
The balanced chemical equation is
[tex]2KOH+H_2SO_4\rightarrow 6H_2O+K_2SO_4[/tex]
According to stoichiometry :
1 mole of [tex]H_2SO_4[/tex] require 2 moles of [tex]KOH[/tex]
Thus 0.0275 moles of [tex]H_2SO_4[/tex] will require=[tex]\frac{2}{1}\times 0.0275=0.0551moles[/tex] of [tex]KOH[/tex]
Mass of [tex]KOH=moles\times {\text {Molar mass}}=0.0551moles\times 56g/mol=3.09g[/tex]
Thus 3.09 g of KOH is required to react completely with 2.70 grams of
[tex]H_2SO_4[/tex]
The particles of a substance lose energy and change from
a disordered structure with large distances between the particles to
a loosely ordered state.
Which change of state is described?
Answer:
A Liquid
Explanation:
structure with large distance (gas) than goes to a loosely ordered state (liquid)
I hope this helps
Potassium hydroxide, also known as lye, dissociates into metal and hydroxide ions in water.
The resulting solution is caustic and used for industrial purposes. What describes the dissociated solution?
O Weak acid
O Strong acid
O Strong base
O Weak base
Answer:
strong acid and weak base
Explanation:
#carryonlearning
In the given question dissociated solution describes the property of the strong base.
What are bases?Bases are substances which gives hydroxide ion into the solution.
Dissociation reaction of caustic soda will be represented as:
KOH → K⁺ + OH⁻
From the above dissociation we conclude that potassium hydroxide is fully dissociates into their ions means it is a strong base and will make the solution caustic.
Weak acid & strong acid is wrong because acids gives H⁺ ion not OH⁻.Weak base is also wrong as weak bases show partial dissociation only.Hence potassium hydroxide is a strong base.
To know more about strong bases, visit the below link:
https://brainly.com/question/7245674
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Characteristics that are used to help identify an object are called
Heart, veins, arteries, capillaries: Which organ system do these belong to?
O
Digestive
Musculoskeletal
Respiratory
Circulatory
Excretory
Answer:
Circulatory
Explanation:
The circulatory system consists of the heart, lungs, arteries, veins, coronary, and portal vessels.
Sarah and Jim investigated the effect of temperature on the solubility of copper sulphate. They dissolved copper sulphate crystals in the same volume of water until no more would dissolve. They measured the mass of copper using water at different temperatures.
One of the mass readings appears to be wrong ( anomalous ) which reading is anomalous? Use the graph to help you.
Answer:
Explanation:
H m sarav
PLEASE HELP ME NO LINKS
Answer: I don’t think the answer is A or C. Maybe B.
The word chemosynthesis means
the synthesis of organic compounds by bacteria or other living organisms using energy derived from reactions involving inorganic chemicals, typically in the absence of sunlight.
Explanation:
WILL RATE BRAINLIST
Your friend works in a bookstore where lab books for science are assembled. Each lab book uses 2 covers, 50 sheets of lined paper, 25 sheets of graph paper and 3 staples. Her inventory includes 150 covers, 7500 sheets of lined paper and 3000 sheets of graph paper and 250 staples. What is the “limiting reactant?” How many complete lab books can be made? How much of each of the other reactants remain in excess?
Answer:
The limiting reactant is the covers.
We are left with 3750 sheets of lined paper, 1125 sheets of graph paper and 25 staples.
Explanation:
the reaction is:
B - book
C - cover
Sl = sheet of lined paper
Sg - sheet of graph paper
St - staple
1B = 2C + 50Sl + 25Sg + 3St
We have covers for 150/2 = 75 books
We have lined paper for 7500/50 = 150 books
We have graph paper for 3000/25 = 120books
We have Staples for 250/3 = 83.(3) books, so for 83 books as we cannot make 1/3 of a book.
Because we only have covers for 75 books, covers are the limiting reactant.
After making 75 books we are left with:
0 covers
7500 - 75*50 = 3750 sheets of lined paper
3000 - 75*25 = 1125 sheets of graph paper
250 - 75*3 = 25 staples
The limiting reactant should be the covers.
We are left with 3750 sheets of lined paper, 1125 sheets of graph paper, and 25 staples.
Calculation of the limiting reaction:
The reaction should be like:
B - book
C - cover
Sl = sheet of lined paper
Sg - sheet of graph paper
St - staple
Now the equation should be
1B = 2C + 50Sl + 25Sg + 3St
We have covers for 150/2 = 75 books
We have lined paper for 7500/50 = 150 books
We have graph paper for 3000/25 = 120books
We have Staples for 250/3 = 83.(3) books, so for 83 books as we cannot make 1/3 of a book.
Now the left should be
7500 - 75*50 = 3750 sheets of lined paper
3000 - 75*25 = 1125 sheets of graph paper
250 - 75*3 = 25 staples
learn more about reaction here: https://brainly.com/question/9230368
Which of Graphs 1 correctly represents the relationship between the pressure and Kelvin temperature of a gas?
Answer:
B
Explanation:
Pressure is directly proportional to temperature
The graph correctly showing the pressure - temperature relationship is figure B. Temperature and pressure is in direct proportionality.
What is Gay- Lussacs law?According to Gay-Lussacs law, at constant volume of gases, the pressure of a gas is directly proportional to the temperature. Thus we can write it as:
P/T = a constant.
Gay-Lussacs law is supportive of kinetic molecular theory. As per kinetic theory of gases, as the temperature increases, kinetic energy of particles increases results in forceful collisions of energetic particles to the wall of container and in between them.
Therefore, the temperature - pressure graph will show a linear relationship. The figure B represents a linear curve and hence it shows the correct relation.
To find more on kinetic theory, refer here:
https://brainly.com/question/15357425
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Mass = 35g Volume = 7cm3 What is the Density?
Answer:
5 g/cm^3
Explanation:√3V=1.91293cm
Emu
Sparrow
How are emus and sparrows alike?
A. Both birds build nests in trees.
B. Both birds are taller than humans.
C. Both birds catch small animals while flying.
U
D. Both birds have a beak for breaking apart food.
what is the molarity of 3.0 L solution containing 250 g of Nal
Answer: C. 0.57 M
Explanation:
Molarity= Moles/Vol
How are the environment of a swamp in a rain forest similar
Jack has a rock. The rock has a mass of 14g and a volume of 2cm3. What is the density of the rock?
Answer:
The density is 7 g/cm^3
Explanation:
The formula for density is p=m/V. Where p is the density, m is mass, and V is the volume. 14/2=7.
Please Help ASAP!!! Will mark Brainliest!!!
A 35 kg child is standing in a 70 kg boat resting on the water. The child jumps forward, away from the boat, pushing with a force of 500 N. After the jump, the boat moves backward.
What does this scenario show?
A. The boat does not exert a force to balance the 500 N force, causing the boat to move.
B. The water creates a frictionless surface, causing the boat to move without an action force.
C. The boat has a greater mass than the child but reacts to an action force.
D. The water beneath the boat absorbs the 500 N force but keeps the boat afloat.
Answer:
A
Explanation:
the boat does not have a force to counter act the boys it must give which means it moves cause it is one something that is not as dense as the boy (I THINK)
How many atoms of aluminum are in 0.1 mol of aluminum?
Answer: The number of 'entities' in a mole of any pure substance is always that. 1 mole is equivalent to the number of atoms in a 12g lump of Carbon12.
Edit: I deliberately avoided using Avogadro's number as that is different, in a technical sense, to a mole. A mole is a base unit of the International System of Units (SI) which recognized amount of substance as an independent dimension of measurement. With this recognition, the Avogadro constant was no longer a pure number but a physical quantity associated with a unit of measurement, the reciprocal mole (mol−1) in SI units.
Therefore Avogadro constant is DERIVED from the mole (nowadays) to give something like 6.02214179 x 10^23 mole^(-1). (based on 2006 evidence)
what is the difinition of the word democracy?
Answer:
Democracy/dɪˈmɒkrəsi/
--noun--
A system of government by the whole population or all the eligible members of a state, typically through elected representatives.
Calculate the molar mass of a solute in a 1.30 L solution with of 0.50 M
containing 10.5 g of the solute.
Answer: 16 g/mol
Explanation: Molarity is Moles/Liters or Mol/L
(0.50 mol/L)(1.30L) = 0.65mol
(cancels out L)
Molar mass is g/mol so...
10.5g/0.65mol = 16.1 g/mol
Rounded to 2 sig figs is 16 g/mol
How many times higher is the concentration of H+ in the Hubbard Brook sample than in unpolluted rainwater?
Answer:
1. 7 (a neutral solution)
Answer: 10-7= 0.0000001 moles per liter
2. 5.6 (unpolluted rainwater)
Answer: 10-5.6 = 0.0000025 moles per liter
3. 3.7 (first acid rain sample in North America)
Answer: 10-3.7 = 0.00020 moles per liter
The concentration of H+ in the Hubbard Brook sample is 0.00020/0.0000025, which is 80 times higher than the H+ concentration in unpolluted rainwater.
Explanation:
How much heat will be produced when 0.58 moles of
hydrogen peroxide (H2O2) decomposes? *
98 kJ + 2H,02(1) → 2H2O(l) + O2(g)
Answer:57.6 kJ
Explanation:
PLEASE HELP!?Consumers must eat other organisms for energy. Which organisms are consumers in this food chain?
Answer:
Consumers must consume other organisms to get the food that they need and are known as Heterotrophs as they cannot make their own glucose. These consumers eat producers (plants). Herbivores are considered as first order consumers. These consumers eat consumers and producers (animals and plants).
Are water waves transverse or longitudinal? How do you know? Own words please. No files or links either.
Answer:
Transverse waves are known by motion being perpendicular to the waves movements. Longitudinal waves move in a direction parallel to the way the wave moves. Water waves are an example of both as they move in a clockwise motion.
Explanation:
( Sorry if it is not the best answer but I did my best by researching )
help? for me? yes? please?
Answer:
2 Mg + O2 -> 2 MgO
is a synthesis reaction.
What effect could the pollution of Groundwater have on a nearby River, Lake or Stream?
Answer:
please give me brainlist and follow
Explanation:
Contamination of ground water can result in poor drinking water quality, loss of water supply, degraded surface water systems, high cleanup costs, high costs for alternative water supplies, and/or potential health problems. The consequences of contaminated ground water or degraded surface water are often serious.
Please help me ASAP I’m almost done.
Answer:
i think the answer is c
Explanation:
sorry if im wrong i am most likely wrong but ye
A train travels 854 meters in 75 seconds. What is the speed of the train?
Answer:
11.3m/s
Explanation: