Answer:
-41. 47
Explanation:
m = q / Cp x T
m = Mass
q = Energy (or joules)
Cp = Heat Capacity
T = Change in Temperature
Water's heat capacity is always 4.18.
This is the formula you'll need for change in temperature:
Final - Initial
So, 33 - 78 = -45
m = 7800 / 4.18 x -45
= -41.47
How many moles are in 7.8 g of acetamide, CH3CONH2?
Answer:
.13 moles
Explanation:
To begin this problem:
First you need to find the molar mass of acetamide, to do so:
C=12g, H=1.008g, O=16g, and N=14g2(12)+5(1.008)+1(16)+1(14)=59.04To find moles when given grams, we divide grams by the molar mass.
7.8g/59.04g/mol=.13 molesUsing 2 sig figs from what we are given, this is our final answer.
How much energy is gained when a 10.0g sample of liquid water increases in temperature from 13°C to 18°C?
Answer:
Your answer is 209 J.
Explanation:
First find △T by subtraction of two temperatures.
△T = 18°C - 13 °C
= 5°C.
Q=mc△t
where,
m= mass.
c = Specific Heat .
t = temperature.
As, Specific Heat capacity of water is 4.18 J/g°C
= 10 × 4.18× 5
= 209 Joules.
When a 10g sample of liquid water increases in temperature from 13°C to 18°C, then the amount of gained energy is 209 joules.
How do we calculate gained energy?The amount of energy which is gained by any sample will be calculated as:
Q = mcΔT, where
Q = gained energy
m = mass of sample = 10g
c = specific heat of water = 4.18 J/g°C
ΔT = change in temperature = 18 - 13 = 5°C
On putting values we get
Q = (10)(4.18)(5)
Q = 209 Joules
Hence required amount of energy is 209 joules.
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Nitrogen and hydrogen react to form ammonia. 12dm of hydrogen reacted with excess nitrogen to form 2dm of ammonia. What is the percentage yield of ammonia at room temperature and pressure.
The percent yield shows the extent to which reactants are converted to products. The percent yield of ammonia is 24.7%
Percent yieldThe percent yield is obtained from the theoretical yield and the actual yield. The reaction between hydrogen and Nitrogen is;
3H2 + N2 ---->2NH3
If 1 mole of H2 occupies 22.4 dm^3
x moles occupies 12dm^3
x = 0.54 moles
If 1 mole of NH3 occupies 22.4 dm^3
x moles of ammonia occupies 2 dm^3
x = 0.089 moles
Now;
From the reaction equation;
3 moles of hydrogen yields 2 moles of NH3
0.54 moles of hydrogen will yiled 0.54 moles * 2 moles/3 moles
= 0.36 moles of ammonia
Percent yield = 0.089 moles/0.36 moles * 100 = 24.7%
The percent yield of ammonia is 24.7%
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Correct formula for barium hydroxide
Ba(OH)2
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What is the mole fraction of Ca3(PO4)2 by dissolving 126.32 g of calcium phosphate, Ca3(PO4)2, in 850 grams of H2O?
Based on the total moles of substance in the solution, the mole fraction of Ca3(PO4)2 is 0.0086
What is mole fraction?Mole fraction is the fractions of the moles of a substance present in a given total moles of a mixture.
The mole fraction = moles of substance/total moles of mixtureMoles of Ca3(PO4)2 is calculated first:
Moles of Ca3(PO4)2 = mass/molar mass
molar mass of Ca3(PO4)2 = 310 g
Moles of Ca3(PO4)2 = 126.32/310 = 0.41
Moles of water = 850/18 = 47.22
Total moles = 47.63
Mole fraction of Ca3(PO4)2 = 0.41/47.22 = 0.0086
Therefore, the mole fraction of Ca3(PO4)2 is 0.0086
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Why does the moon and the sun have the same mass.
Why does the moon and the sun have the same mass?
Answer: The difference is that, on the moon, you are much lighter than on the Earth, but you still have the same mass
Consider the entropy change in the following chemical or physical processes:
1.2 Na(s) + Cl₂(g) → 2 NaCl(s)
2. N₂(g) + 3 H₂(g) → 2 NH3(g)
3. H₂O(s)→ H₂O(l)
4. C10H22(1)→ C10H22(S)
5.2 Mg(s) + O₂(g) → 2 MgO(s)
In which of these processes is entropy increased?
Answer:
D
Explanation:
Recall that entropy measures the number of microstates in a substance, which is highest in gases, followed by liquids and solids. Hence, entropy increases if the products have more gaseous molecules than the reactants.
In reaction one, chlorine gas is converted into solid NaCl, so entropy decreaes. In reaction two, four moles of gas are converted into two moles of gas, so entropy decreases. In reaction three, ice is melted to form water, which has higher entropy. Thus, entropy increases. In reaction four, a liquid is freezed into its solid phase, leading to a decrease in entropy. In reaction five, oxygen gas is converted into solid MgO, so entropy decreases.In conclusion, the answer is D.
write any five prevention of cancer
Answer:
Don't use tobacco or tobacco-containing products
Maintain a healthy diet
Protect yourself from the sun, make sure to use sunscreen
Go to the doctor regularly, for general checkups
Stay physically active
Explanation:
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Additional purchases may be added in open-end credit.
True
False
2. Which is not true of an electric current?
A. An electric circuit provides a path for electric current to follow.
B. Electric current exists in all materials.
C. Electric current requires a specific path to follow.
D. If an electric circuit is broken, electric current will not flow.
On a long bus trip, a traveler does
not drink
any water for several hours. How
will the volume of urine she produces that day
compare to the volume on a day when she
drinks several glasses of water? Explain.
Answer:
The volume will be less.
Explanation:
The volume of urine someone produces varies based on their liquid intake. The more liquid you intake, the more you must urinate (not a direct correlation, but basically).
Both mass and weight provide a measure of the amount of matter in an object. Mass is the preferred measure because:
a. mass is independent of location.
b. mass is dependent on location.
c. mass is easier to measure.
d. mass is measured using the metric system.
Answer:
I think it's because mass is independent of location
Answer:
A
Explanation:
mass doesn't change from changes in gravity unlike weight
Jane was drinking a glass of water. She asked her father where the water
came from. Her father said it was groundwater that was pumped up by their
well. Jane wondered what the water looked like underground. This is what
her family said:
Mom: I think it looks like a huge ocean underground.
Dad: I think it looks like a small lake underground.
Jack: I think it seeps into little holes or spaces between the soil and the
rocks.
Annie: I think it looks like a long, underground tube filled with water.
Philip: I think it looks like an underground volcano with water spurting out
of the top.
Which person do you agree with the most
Janes brother Jack is actually correct, underground water seeps into little holes or spaces between the soil and the rocks.
Underground WaterSimply put, underground water is found in between soils and crack, another name for this is called aquifers were water is found.
It should be noted that underground water are found at varying levels depending the terrain.
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measuring masses of the reactants (Reaction 2) Step 7
pls help me with thiss
Answer:
D. Large body of lava
Explanation:
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A particle has a velocity that is 70 % of the speed of light and weighs 206.8 times the mass of an electron. Find the wavelength of this particle?
What is the final temperature of a system if 18.00 g of gold at 90.0°C is placed in 18.00 g of water at 26.00°C? The molar heat capacity of gold is 25.41
J/(mol • °C) and the heat capacity of water is 4.18 J/g. °C).
Given,
Molar heat capacity of gold is 25.41 J/(mol • °C)
Heat capacity of water is: 4.18 J/g. °C)
use the capacities to calculate the resultant temperature of the system using the mass of 18 grams of gold alongside 18 grams of water.
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What is another word for a substance that is a base?
A.
indicator
B.
amphoteric
C.
buffer
D.
alkaline
Answer:
D) alkaline
Explanation:
What is the distinguishing characteristic of invertebrates?
Group of answer choices
Specialized tissues and organ systems
The lack of a centralized brain
The lack of a spinal column
Being an insect
The lack of a spinal column is the distinguishing characteristic of invertebrates.
What is an Invertebrate?These are organisms which lack a backbone(vertebral column) while vertebrates on the other hand have it.
This is why option C was chosen as the most appropriate choice in this scenario.
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a) Is ethanoic acid a weak electrolyte or a strong electrolyte, give a reason for your answer. Show the dissociation of ethanoic acid in water.
Answer:
Acetic acid is a weak electrolyte because its dissociation constant is small meaning there will be few ions in solution to conduct electricity.
Weak electrolyte are very less or partially ionized and strong electrolytes are completely ionized or 100% ionized. Ethanoic acid is weak electrolyte.
How to determine whether a acid is weak or strong electrolyte ?
To determine whether the acid is strong electrolyte or weak electrolyte check whether it is completely ionize or partially ionized. The molecular formula of ethanoic is [tex]CH_3COOH[/tex] and ethanoic acid is also called acetic acid. Ethanoic acid is weak electrolyte because it does not dissociate very much.
The dissociation of ethanoic acid in water:
[tex]CH_{3}COOH_{(aq)} + H_{2} O_{(l)}[/tex] ⇄ [tex]CH_{3}COO^{-}_{(aq)} + H_{3}O^{+}_{(aq)}[/tex]
Thus, from above conclusion we can say that Ethanoic acid is weak electrolyte and the dissociation of ethanoic acid in water is: [tex]CH_{3}COOH_{(aq)} + H_{2} O[/tex] ⇄ [tex]CH_{3}COO^{-}_{(aq)} + H_{3}O^{+}_{(aq)}[/tex]
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For a certain reaction with an average percentage yield of 80 %; if the theoretical yield was 5.0 g then the actual yield will be ?
The actual yield of the reaction is 4.0 g, given that the percent yield of the reaction us 80% and the theoretical yield is 5.0 g.
What is percent yield of a reaction?The percent yield of a reaction is the amount of actual product obtained from a reaction taken as a ratio of the expected amount of product expressed in percentage.
Percent yield = actual yield/theoretical yield × 100%Given that the percent yield of the reaction us 80% and the theoretical yield is 5.0 g.
Actual yield = 80% × 5.0 = 4.0 g
Therefore, the actual yield of the reaction is 4.0 g.
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Do you think precipitation has a greater impact on the rate of chemical weathering or mechanical weathering? Explain
Greater rainfall has an greater increase on the rate of chemical weathering. Rain is a form of precipitation.
Ideal Gas Law 1
Calculate the volume of 3.00 g of carbon dioxide gas at 288K and 123.3 kPa.
Give your answer in litres to three significant figures. Do not include units.
Answer:
1•323
Explanation:
mass of carbon=12
mass of oxygen=2*16=32
no of moles = 3/44
PV=nRT
V=(0.06818*8.31*288)/123.3*10^3
What is the product of photosynthesis that plants make as a source of energy for their life functions? What role does this substance have in your life?
Answer:
Glucose. Also provides heat and energy in man
Explanation:
I hope this right if ain't I'm sorry
A 53.8 g sample is burned in a bomb calorimeter. If the temperature rose from 32.0 oC to 56.0 oC and the heat capacity of the calorimeter is 13.3 kJ/oC, what is the value of ΔHrxn (in kJ/mole of sample)? The molar mass of the sample is 56.23 g/mol.
Based on the heat absorbed by the calorimeter, the heat of reaction, ΔHrxn is 333.5 kJ/mol
What is the heat evolved by the sample?The heat evolved or given out by the sample is the equal to the amount of heat absorbed by the calorimeter.
The heat absorbed by calorimeter is given as:
Heat = specific heat capacity × temperature differenceHeat = 13.3 × (56.0 - 32.0)
Heat evolved = 319.2 kJ
Moles of sample reacted = 53.8/56.23 = 0.957
ΔHrxn = 319.2 kJ/0.957 moles = 333.5 kJ/mol
Therefore, the heat of reaction, ΔHrxn is 333.5 kJ/mol.
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Please help!!
How many O2 molecules occupy a 1.0 L flask at 65°C and
103.7 kPa?
Select one:
O a. 28 molecules
O b. 2.2 x 1022 molecules
O c.
1.1 x 1023 molecules
O d.
1.6 x 1025 molecules
e. 1.7 x 1025 molecules
Answer:
B, 2.22×10^22 molecules
Explanation:
Given PV=nRT, n=PV/RT
n=103.7×1.0/8.314×(65+273.15)
= 0.0368858... moles
Given n= number of particles/avogadros number
number of particles=n×avogadros number
number of particles = 0.03688...×6.02x10^23
= 2.22×10^22 molecules
i need this done by tonight!!! GIVING BRAINLIEST TO CORRECT ANSWER
Match the terms to their definition.
Water circulation created by prevailing wind systems. The Gulf Stream is an example.
The length of open sea over which wind can blow steadily to create waves.
The amount of dissolved salt in a liquid.
The distance from the crest of one wave to the crest of another.
Water circulation created by differences in density.
This is what moves forward and through a wave.
The cyclical process of the changing state and movement of water around the Earth through evaporation, condensation, and precipitation.
As the amount of salt in water increases, the density of the water _________.
The type of energy possessed by moving water.
The rising of ocean water bringing nutrients up from the deep.
1.
The water cycle
2.
vapor transport
3.
salinity
4.
increases
5.
decreases
6.
surface currents
7.
Coriolis Effect
8.
deepwater currents
9.
trough
10.
wave period
11.
wavelength
12.
water molecules
13.
energy
14.
crest
15.
fetch
16.
electrical
17.
kinetic
18.
downwelling
19.
upwelling
Answer:
Gulf Stream. The Gulf Stream is a warm surface ocean current which originates in the Gulf of Mexico and flows northeast across the Atlantic, driven by the prevailing southwest winds. It influences the climate of the UK and Northwest Europe by bringing with it humid mild air.
Isocyanic acid, also known as Hydrogen cyanate, is a weak acid and a potentially toxic atmospheric pollutant. Write down the equation for the dissociation of isocyanic acid in water. Explain the term conjugate base and state the correct conjugate base of isocyanic acid. Give a reason for your answer.
The dissociation of isocyanic acid in water produces its conjugate base, C N- since it will accept a proton to form isocyanic acid.
What is a conjugate base?A conjugate base is a substance which is formed from the loss of the hydrogen ion of an acid and which will act as a base by accepting a proton.
The dissociation of Isocyanic acid in water is given below:
[tex]HC N + H_2O \rightleftharpoons C N^{-} + H_3O^{+}[/tex]
The conjugate base is C N- since it will accept a proton to form isocyanic acid.
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(2 Question 6 Without modifying the apparatus, how could the reliability of the results be increased?
Explanation:
Reliability can be improved by completing each temperature more than once and calculating an average.
How many times more soluble is scandium fluoride in pure water than it is in a solution that is 0.00837 M in potassium fluoride? ScF3 (s) <---> Sc3+ (aq) + 3 F- (aq), Ksp = 5.81 x 10-24.
Scandium fluoride is 1.56 * 10¹¹ times more soluble in pure water than it is in a solution that is 0.00837 M in potassium fluoride.
What is the molar solubilty of scandium fluoride in pure water and in 0.00837 M potassium fluoride?The molar solubilty of scandium fluoride in pure water and in 0.00837 M potassium fluoride is calculated from the Ksp value of Scandium fluoride.
Equation for the dissolution of scandium fluoride in water is given below:
[tex]ScF_3 \rightleftharpoons Sc^{3+} + 3F^{-}[/tex]Molar solubilty in pure water is calculated thus:
[tex][Sc^{3+}] = x; [F^{-}] = x[/tex]
[tex]K_{sp} = [Sc^{3+}] * [F^{-}]^{3}[/tex]
[tex]5.81 *10^{-24} = x * x^{3} = x^{4}[/tex]
x = 1.55 * 10⁻⁶ M
Molar solubilty in 0.00837 M potassium fluoride is calculated thus:
[tex][Sc^{3+}] = x; [F^{-}] = (0.00837 + x)[/tex]
[tex]K_{sp} = [Sc^{3+}] * [F^{-}]^{3}[/tex]
[tex]5.81 *10^{-24} = x * (0.00837 + x)^{3}[/tex]
Since the Ksp value is very small, we assume that x <<< 0.008367, therefore;
[tex]5.81 *10^{-24} = x * (0.00837)^{3}[/tex]
x = 9.91 * 10⁻¹⁸ M
Comapring the molar solubilties in water and in 0.00837 M in potassium fluoride:
1.55 * 10⁻⁶ M/9.91 * 10⁻¹⁸ M = 1.56 * 10¹¹
Therefore, scandium fluoride is 1.56 * 10¹¹ times more soluble in pure water than it is in a solution that is 0.00837 M in potassium fluoride.
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