312 grams of oxygen reacts.
Balanced chemical equation for the reaction of hydrogen and oxygen to produce water: 2H₂ + O₂ → 2H₂O.
m(H₂) = 39.3 g; mass of hydrogen
n(H₂) = m(H₂) ÷ M(H₂).
n(H₂) = 39.3 g ÷ 2 g/mol.
n(H₂) = 19.65 mol; amount of hydrogen
m(H₂O) = 351 g; mass of water
n(H₂O) = 351 g ÷ 18 g/mol
n(H₂O) = 19.5 mol; amount of water
From chemical equation: n(O₂) : n(H₂O) = 1 : 2
n(O₂) = 19.5 ÷ 2
n(O₂) = 9.75 mol; amount of oxygen
m(O₂) = 9.75 mol × 32 g/mol
m(O₂) = 312 g; mass of oxygen
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determine the number of moles of methane in 120cm³ of the gas at r.t.p
Answer:
0.005 moles
Explanation:
120cm^3 = 0.12dm^3
1mol is always 24dm^3 of gas at rtp
0.12 ÷ 24 = 0.005 moles
What is the proper solution to the following
equation?
(150. + 2.5+ 36.75) ÷ (6.60+ 0.173)
=
A)30
B)27.94
C)28
D)27.942
E) 27.9
Answer:
B) 27.94
Explanation:
All other last digits are wrong except b
Answer:
[tex] \frac{39.25 + 150.}{6.773} = 27.94182[/tex]
Explanation:
[tex]1. \: (39.25 + 150.) \div (6.60 + 0.173) \\ 2. \: (39.25 + 150.) \div 6.773 \\ 3. \: (39.25 + 150.) \times \frac{1}{6.773} \\ 4. \: \frac{(39.25 + 150.) \times 1}{6.773} \\ 5. \: \frac{39.25 + 150.}{6.773} = 27.94182[/tex]
How do firefighters use their knowledge of the fire triangle to help them control fires? how do the measures they take relate to the chemistry involved?.
Answer:
okay
Explanation:
The fire triangle's three sides illustrate the three elements of fire: heat, fuel and oxidization. The three elements must be combined in the right proportions for a fire to occur. If any of the three elements are removed, the fire is extinguished
bro i need help asap
A rectangular block of copper metal weighs 1996 g. The dimensions of the block are 9.4 cm by
6.5 cm by 5.6 cm. From this data, what is the density of copper? (hint: find the volume of a block
first)
Question 20
What element is represented in the following notation [Ne] 3s² 3p4
OS
OC
O Mg
O AI
<< Previous
5 p
Answer: S
:) hope this helps you!
Calculate the ph of a buffer solution obtained by dissolving 17.0 g of kh2po4(s) and 30.0 g of na2hpo4(s) in water and then diluting to 1.00 l.ph=
The ph of a buffer solution was obtained by dissolving 17.0 g of [tex]KH_{2} PO_{4}[/tex] and 30.0 g of [tex]Na_{2} HPO_{4}[/tex] in water and then diluting to 1.00L is 7.43.
We will apply the Henderson-Hasselblach equation to determine the pH:
pH= pKa + Log [A/AH]
when [tex]Na_{2} HPO_{4}[/tex] molar mass is 142 g/mol
A is the conjugate base [tex]HPO_{4} ^{-}[/tex] ions and as a result,
[tex][A]= \frac{30g}{142 g/mol}[/tex]
= 0.211 M
[tex]KH_{2} PO_{4}[/tex] has a molar mass of 136 g/mol.
Given that AH is the weak acid [tex]H_{2} PO_{4} ^{-}[/tex] ion,
[AH] = [tex]\frac{17.0 g}{136 g/mol.}[/tex]
= 0.125 M
and with [tex]H_{3} PO_{4}[/tex] having a pKa value of 7.21
then, substituting
∴ pH = 7.21 + log (0.211 / 0.125)
= 7.21 +0.227
=7.43
The pH of a buffer solution is 7.43.
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When performing an extraction with between an aqueous solution and organic solution what determines which layer ends up the bottom layer in the separatory funnel ?.
When performing an extraction between an aqueous solution and an organic solution or organic compound, density will determine the layer ending up at the bottom of the separation funnel.
In chemistry, a separatory funnel is a kind of funnel that separates two immiscible liquids.
It is a transparent funnel and when two immiscible liquids i.e aqueous and organic solution is poured into it, and then allowed to stand, after a while a distinguished layer is formed setting them apart from each other.
Due to the difference in density, the extraction becomes easier as the aqueous layer has a low density and stays at the top while the organic layer is at the bottom.
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Chemically speaking, how does applying hot dog mustard to a coin detect the presence of silver metal
Answer:
A black spot will remain on the silver coin, but not on the nonsilver coin. Mustard naturally contains sulfur compounds, and sul- fur reacts with silver to form a black precipi- tate of silver sulfide (Ag2S)
Explanation:
Uranium has three isotopes with the following percent abundances: 234- (0.0058%), 235- (0.71%), 238- (99.23%). Without doing any calculations, what do you expect the atomic mass of uranium to be in whole numbers. Why?
Answer:
Because it is the same element but has different atomic mass
convert 3 hrs into sec by dimensional analysis
[tex]=3h\ x\ \frac{60 \min}{1h }\ x\ \frac{60\ sec}{1\ min}[/tex]
[tex]=10800\ sec[/tex]
Set up your equation so that your units cancel until you get to the unit you want. Hours and hours would cancel, and min and min would cancel, leaving you with sec which is the unit you want.
Remember: they can only cancel if one is on top and the other is on the bottom.
Answer:
1hr=60minutes
1min=60 seconds
then we have to convert 3hrs into seconds
now,
3*60*60=10,800
Calculate the ratio of the concentration of formate to formic acid required in a buffer system of ph 4.25. the pka of formic acid is 3.75. ratio = ________________.
The ratio of the concentration of formate to formic acid required in a buffer system is 3.16 : 1.
pH = 4.25; pH of the solution
pKa = 3.75
Henderson–Hasselbalch equation: pH = pKa + log(cs/ck)
4.25 = 3.75 + log(cs/ck)
log(cs/ck) = 4.25 - 3.75
log(cs/ck) = 0.5
cs/ck = 10∧(0.5)
cs/ck = 3.16; ratio of formate to formic acid
A buffer can be defined as a substance that prevents the pH of a solution from changing by either releasing or absorbing H⁺ in a solution.
Buffer is a solution that can resist pH change upon the addition of an acidic or basic components and it is able to neutralize small amounts of added acid or base, pH of the solution is relatively stable.
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Which of the following scenarios could be considered evidence of a compound with a low activation energy?
A. a high amount of naturally occurring NaCl
B. a low amount of spontaneous fuel combustion
C. a low amount of collisions between molecules
D. a high amount of heat required to form products
A high amount of naturally occurring NaCl is considered evidence of a compound with a low activation energy and is denoted as option A.
What is Activation energy?This is referred to as the minimum amount of energy which is needed for a chemical reaction to occur and is dependent on various factors.
A compound which has a low activation energy will have a high yield sue to the ease in which the reactants are being converted into products. in this scenario, the high amount of naturally occurring NaCl signifies a low activation energy which is why option A was chosen as the correct choice.
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Describe scientific method
The scientific method is an experimentation technique used to investigate data and answer questions. All sciences, including chemistry, physics, geology, and psychology, follow the scientific method. These scientists ask various questions and conduct different tests. They do, however, apply the same fundamental technique to arrive at logical and evidence-based conclusions. Scientists change the scientific method when direct experimentation is not possible. Understanding the phases of the scientific process can assist you in focusing your scientific inquiry and working through your observations and data to get the best possible response.
The scientific method consists of seven phases.
1. Pose a query. The scientific approach begins with posing a question that you want answered.
2. Conduct research.
3. Create your theory.
4. Experiment to put your hypothesis to the test.
5. Make a note of it.
6. Analyze the findings and reach a conclusion.
7. Display your results.
A chemist heats a 215-g sample of iron from 25.0°C to 90.0°C. How much heat did the iron absorb? The
specific heat capacity of iron is 0.45 J/g°C.
A 215-g sample of iron is heated by a chemist from 25.0°C to 90.0°C and 6.3 kJ of heat are absorbed by the iron (q).
What is meant by specific heat?Also known as specific heat, this is the quantity of energy required to increase a substance's temperature by 1 degree Celsius in one gram. The units of specific heat are typically calorie or joules a gram per degree Celsius. As an illustration, the specific heat of water is 1 calorie (4.186 joules) each gram per degrees C.
Briefing:q = m × C × ΔT
q = m × C × (T[tex]_f[/tex] - T[tex]_i[/tex]),
q is the quantity of heat energy a substance gains or loses (J)
m = mass of sample (g)
C = specific heat capacity (J °C-1 g-1)
T[tex]_f[/tex] = final temperature (°C)
T[tex]_i[/tex] = initial temperature (°C)
Thus:
q = (215 g) × (0.45 J oC-1 g-1) × (90 - 25)°C
q = 6288.75 J
q = 6288.75 J = 6.3 kJ
The iron absorb 6.3 kJ of heat (q).
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4. How many seconds in 1.0 yr?
Answer:
Around 31536000 seconds (depending on which days you want to exclude)
Explanation:
60 seconds in 1 minute
60 minutes in an hour
24 hours in 1 day
365 days in 1 year
60 * 60 * 24 * 365
Why do industries use metallic compounds to make wires?
Select all that apply.
Responses
metallic compounds often have high luster
metallic compounds often have high luster
metallic compounds are ductile
metallic compounds are ductile
metallic compounds have high boiling points
metallic compounds have high boiling points
metallic compounds are good conductors of electricity
metallic compounds are good conductors of electricity
Answer:
metallic compounds are good conductors of electricity.
metallic compounds have high boiling points
To determine the molar mass of an unknown from the freezing point depression, the freezing points of both the pure solvent and the solution need to be measured.
Yes, to determine the molar mass of an unknown solute from the freezing point depression the freezing points of both the pure solvent and the solution need to be measured.
The depression of the freezing point is a and it is given by the following formula,
ΔT f = T°f - T f
Here T°f is the freezing point of pure solvent
T f is the freezing point of the solution made by adding non-volatile solute to solvent
The freezing point depression is directly proportional to the molality of the solution
T(f) ∝ m
T(f)= K f x m
Here K f is the proportionality constant.
Hence, to determine the molar mass of an unknown solute from the freezing point depression the freezing points of both the pure solvent and the solution need to be measured.
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At a track meet the officials use a timer to determine the amount of time it takes to complete each running event. If the timer does not function correctly and adds one second onto each runner's time this is an example of a random error. true or false
Answer:
This is an example of a random error because the timer is adding an extra second onto each runner's time, which is not an accurate representation of their true time. This error is not systematic, meaning that it does not affect all runners in the same way or add the same amount of time onto their times.
Explanation:
Give me brainliest if that helped :)
HELP.....................................................
Answer:
I believe that would be a liquid.
Explanation:
Calculate the molality of a solution containing 15.01 g of glycerol (c 3h 8o 3) in 42.3 g of ethanol (c 2h 5oh).
The molality of the glycerol solution is 3.854mol/kg
The number of moles of solute present in a solution equal to 1 kg or 1000 g of solvent is referred to as its molality.
Given:
Mass, m1 of glycerol = 15.01g
Mass, m2 of ethanol = 42.3g
Molar mass, mm1 of glycerol = 92.095g/mol
Molar mass, mm2 of ethanol = 46.069g/mol
To find:
Molality, m = ?
Formula:
Molality, m = moles of solute / kg of solvent
Calculations:
No. of moles of glycerol = 15.01 x (1/92.095)
n = 0.163 mols
Molality, m = 0.163 / 0.0423g
Molality, m = 3.854mol/kg
Result:
3.854mol/kg is the molality of the glycerol solution.
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How does the idea of quantized energy apply to Bohr’s atomic model?
Answer:the electrons can possess only certain discrete energy values; values between those quantized values are not permitted.
Explanation:Both involve a relatively heavy nucleus with electrons moving around it, although strictly speaking, the Bohr model works only for one-electron atoms or ions.
Please share the answers with explanations
Thanks,
The melting and boiling and density is given below :
Substance melting point / °C boiling point / °C density / g cm⁻³
E -259 -253 0.09
F 1085 2580 8.93
G -7 59 3.1
H -39 357 13.6
I -218 - 183 0.0013
A) substances are gases at room temperature:
E and I are gases at room temperature because the melting and boiling point are below at room temperature.
B) substances are liquids at room temperature:
G and H are liquids at room temperature because substances are liquid at room temperature if melting point is below room temperature and boiling point is above room temperature.
C) substances are solid at room temperature :
F is solid at room temperature because its melting point is above room temperature.
D) substances are most likely to be metal :
F is metal because metals have very high melting and boiling point except mercury.
E) substance are most likely to be mercury :
H is most likely to be mercury because mercury has boiling point -38°C and melting point is 356°C and density is 13.5 g/ cm³ and mercury is metal with exception.
G) substances will be liquid at -210°C :
I is liquid at -210°C because substance is liquid when its melting point is below temperature and boiling point is above temperature.
H) substances are most likely to be bromine :
G is more likely to be bromine because melting and boiling point and density of G is close to bromine.
I) substances which are least dense non metal :
E is least dense non metal because its melting and boiling point and density is close to least dense non - metal.
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A 6.67 mg sample of a compound containing carbon, hydrogen, and oxygen underwent combustion producing 15.17 mg of CO2 and 6.19 mg of H2O. What is the empirical formula of the compound? (Type your answer using the format CxHyOz for the compound CxHyOz)
The empirical formula of the compound is C₃H₆O
What is the empirical formula of the compound?The empirical formula is determined as follows from the equation of the reaction as follows:
CxHyOz + O₂ → x CO₂ + y/z H₂Omass of CO₂ produced = 15.17 mg = 0.01517 g
moles of C in the sample = 0.01517/44 = 0.000344 moles
mass of C in the sample = 0.0000344 * 12 = 0.00413 g
mass of H₂O produced = 6.19 mg = 0.00619 g
moles of H in the sample = 0.00619/18 * 2 = 0.000688 moles
mass of H in sample = 0.000688 g
mass of oxygen in the sample = 0.00667 g - (0.00413 g + 0.000688 g)
mass of oxygen in the sample = 0.00185
moles of oxygen = 0.00185/16 = 0.000116
Ratio of C : H : O = 0.000344 : 0.000688 : 0.000116
Ratio of C : H : O = 3 : 6 : 1
Empirical formula of compound = C₃H₆O
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Students conducted an analysis of baking soda in chemistry lab. During the activity, they had to calculate the mass in
grams of the baking soda being used. Some student data appears in the table. At the end of the activity, the teacher
told the students that the actual mass of baking soda was 0.45 grams. Which student had the most accurate and
precise data?
The student that had the most accurate and precise data is Mel (option D).
What is accuracy and precision?Accuracy is the degree of conformity of a measure to a true or standard value i.e. closeness to a standard or true value.
On the other hand, precision is the ability of a measurement to be reproduced consistently i.e. the closeness of measured values.
According to this question, students calculated the mass in grams of the baking soda being used.
It can be said that Mel, which measured the following values: 0.44g, 0.46g, 0.45g had the most accurate and precise value because they are both close to themselves and the true value.
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Answer:
D
Explanation:
Mel
What mass of ammonia is formed when 5.36 g of nitrogen gas reacts with excess hydrogen gas?
6.508 g mass of of NH3 is formed when 5.36 g of nitrogen gas reacts with excess hydrogen gas.
N2 + 3 H2 → 2 NH3
The molar mass of N2 is 28.0 g/mol. The molar mass of NH3 is 17 g/mol.
To find the mass of NH3:
=5.36 x 2 x (17 / 28)
=182.2 / 28
= 6.508 g
The mass of ammonia is 5.36 g.
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What is the formula for Newtons second law of motion 
Answer: F=m*a
Explanation: Force equals mass times acceleration!
I hope this helps!
If+a+monoprotic+weak+acid,+ha,+is+80%+ionized+at+a+concentration+of+0.05+m,+what+is+the+ph?
The pH of a monoprotic weak acid which is 80 percent ionised with a strentght of 0.05m is 1.39
What is pH ?
A scale called pH , which traditionally stood for "potential of hydrogen" (or "power of hydrogen"), is used in chemistry to describe how acidic or basic an aqueous solution is. Lower pH values are recorded for acidic solutions (solutions with higher H+ ion concentrations) than for basic or alkaline solutions. The concentration of hydrogen ions in the solution is shown inversely by the pH scale, which is logarithmic.
pH + pOH = 14
[H + ]=0.05×0.80=0.04M
Now, Here, pH=−log[H + ]=−log0.04=1.39
The pH of a monoprotic weak acid which is 80 percent ionised with a strentght of 0.05m is 1.39
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Which of the following science and engineering practices describes one the first things that scientists do when starting a new investigation?
A) Constructs an Explanation
B) Interprets data
C) Designs a solution
D) Ask a question
Ask a question the first things that scientists do when starting a new investigation.
What are scientific practices?Scientific practices, which include things like answering questions, creating and using models, and having arguments, are cognitive, discursive, and social activities carried out in science classrooms with the goal of developing epistemic understanding and appreciation of the nature of science.
Why are the science and engineering practices important?Participating in these activities not only makes students' knowledge more meaningful and deeply ingrained in their worldview, but it also aids them in developing an understanding of the disciplinary and transdisciplinary ideas of science and engineering.
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1. Calculate the volumes of the samples used in Procedure step 2. Record the calculated
volumes in Table 2.2. Why could we not find the volume of the bolt by this method?
From the table shown in the question;
Volume of aluminum bar = 15.52 cm^3
Volume of the rod = 23.8 cm^3
The volume of the iron bolt can only be obtained by the displacement method.
What is volume?The term volume refers to the space that is occupied by an object. We know that the volume of an object could be obtained in different ways depending on the nature of the object. If the object is a solid, we could look at the dimensions of the solid or we could use the dimensions of the solid. The actual method that we finally use is peculiar to the object whose volume we intend to measure.
In order to obtain the volume of the aluminum bar;
Volume = length * width * height
Volume = 9.7 * 1.6 * 1.0 = 15.52 cm^3
In order to obtain the volume of the rod;
Volume = Area * length
Volume = 3.14 * (1.7)^2/4 * 10.5
Volume = 23.8 cm^3
We can not obtain the volume of the iron bolt by this method because it is an irregular solid hence we have to use the displacement method.
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