what might happen to variables in a science experiment that would lead to unusable results?
Answer:
ejeb094
Explanation:
nnb3neneie9eei rje
The half-life of cesium-137 is 30 years. Suppose that we start with 70 grams of cesium-137 in a storage pool. How many half-lives will it take for there to be 10 grams of cesium-137 in the storage pool?
Answer:
Explanation:
Let n be number of half lives taken .
10 = 70 x ( 1/2 )ⁿ
1/7 = ( 1/2 )ⁿ
2ⁿ = 7
n ln2 = ln 7
n = ln7 / ln2
= 1.9459 / .693
= 2.8
So 2.8 half lives will be required .
what element has a higher ionization energy carbon or silicon
WhatGiven the particle diagram:
Which type of matter is represented by the particle diagram?
(1) an element
(2) a compound
(3) a homogeneous mixture
(4) a heterogeneous mixture
Answer:
A compound
Explanation:the mixture can vary
What does this image represent?
a) alcohol group
b) carbonyl group
c) ether group
d) hydroxyl group
Explanation:
It represent Alcohol group (—OH)
Can you guys answer question 4 on new substance for Chemistry tysm
The answer is a bevasue it then becomes a chemical compound
Answer:
a
Explanation:
this would result in a compound and compounds are chemical changes so i think im right....
explain the reason each step of the separation is performed with three portions of the solvent rather than with a single poriton of solvent
Answer:
Several extractions is more effective than a single extraction.
Explanation:
When extraction is carried out multiple times, for instance, in this case, the extraction was carried out with three portions of the solvent rather than with just a single portion of the solvent, the amount of material left in the residue will be lower, because the extraction is more complete.
Several extractions with smaller volumes of solvent are more effective than a single extraction with a large volume of solvent.
Quick electron emissions are called
Write a balanced equation for the double-replacement precipitation reaction described, using the smallest possible integer coefficients. A precipitate forms when aqueous solutions of lead(II) nitrate and sodium hydroxide are combined.
Answer: [tex]Pb(NO_3)_2(aq)+2NaOH(aq)\rightarrow 2NaNO_3(aq)+Pb(OH)_2(s)[/tex]
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
The balanced chemical equation for a precipitate forms when aqueous solutions of lead(II) nitrate and sodium hydroxide are combined is:
[tex]Pb(NO_3)_2(aq)+2NaOH(aq)\rightarrow 2NaNO_3(aq)+Pb(OH)_2(s)[/tex]
3. What is the Limiting Reactant in the following equation if you start with 3 moles of NH3 with 6 moles of O2?
4NH3 (g) + 5O2 (g) 4NO (g) + 6H2O(g)
4. How many grams of NO can be made from the previous equation and quantities?
Answer:
3. NH3 is limiting
4. 90 g NO
Explanation:
3. To find the limiting reactant, you have to convert from moles of reactant to moles of product. In this case, because we need to know how many grams of NO in the second question, we will use NO as our product. We use the ratios found in the chemical formula.
[tex]3 mol NH3*\frac{4 molNO}{4 mol NH3} = 3molNO[/tex]
[tex]6 mol O2*\frac{4 molNO}{5 mol O2} = 4.8molNO[/tex]
Because NH3 makes less moles of NO, it is the limiting reactant.
4. Now we need the molar mass to convert the moles of NO into grams of NO. The molar mass of NO is 30.01g/mol. This is the equation.
[tex]3 mol NO*\frac{30.01g NO}{1 mol NO} = 90.03gNO[/tex]
Because there are is only one significant figure in the original numbers, we round to one significant figure = 90 g NO.
I2(g) + Br2(g) ↔ 2 IBr(g) What is the equilibrium concentration of IBr (in M to 4 decimal places) if 0.200 mol of I2 and 0.100 mol Br2 in a 5.00 L vessel if Kc = 29 at 150°C?
Answer:
The equilibrium concentration of IBr is 0.0360 M or 0.1032 M
The equilibrium concentration of IBr is 0.752 mol
Explanation:
Mathematically, concentration = number of moles/volume
For Iodine molecule, concentration = 0.2/5 = 0.04 M
For the bromine molecule, concentration = 0.1/5 = 0.02 M
We need to set up an ICE table ( Initial, change, equilibrium) to get the concentrations of the molecules at equilibrium.
Please check this table in the attachment.
From the table, we can see that the equilibrium concentration of Iodine is (0.04-x), that of Bromine is (0.02-x) while that of IBr is 2x
Now, we need to get the equilibrium constant using the equilibrium concentration of the molecules
With the given chemical reaction, we can represent the equilibrium constant in terms of pressure as follows;
Kc = [IBr]^2/[Br2][I2]
Thus;
Kc = (2x)^2/(0.04-x)(0.02-x)
Kc = 4x^2/(0.04-x)(0.02-x)
From the question, Kc = 29 , so substitute this;
29 = 4x^2/(x^2-0.06x+0.008)
Cross multiply
29((x^2-0.06x+0.008) = 4x^2
29x^2 - 1.74x +0.0232 = 4x^2
Thus;
25x^2 - 1.74x + 0.0232 = 0
Solving this quadratic equation, we get two values for x which are x = 0.0516 and 0.0180
The equilibrium concentration is either (2 * 0.018) or (2 * 0.0516) which is 0.0360 or 0.1032
True or false this model represents an ion
Answer:
False
Explanation:
From the question given above, the following data were obtained:
Electron number = 6
Proton number = 6
Neutron number = 6
From the question given above, we can see clearly that the model has the same number of protons and electrons. Hence the model is not an ion.
This can further be explained if we determine the charge.
Electron number = 6
Proton number = 6
Charge =?
Charge = Proton – Electron
Charge = 6 – 6
Charge = 0
Since the charge is zero, the model is not an ion.
A first-order decomposition reaction has a rate constant of 0.00140 yr−1. How long does it take for [reactant] to reach 12.5% of its original value? Be sure to report your answer to the correct number of significant figures.
Reactants take 504.87 yr to reach 12.5% of their original value in first-order decomposition reaction.
Equation for the first-order decomposition reaction:-[tex]A_{t} =A_{0} e^{-kt}[/tex]....(1)
Here, [tex]A_{t}[/tex] is the final concentration, t is the time, [tex]A_{0}[/tex] is the initial concentration, and k is the rate constant.
Given:-
[tex]A_{t} =0.125A_{0}[/tex]
k= [tex]0.00140yr^{-1}[/tex]
Substitute the above value in equation (1) as follows:-
[tex]0.125A_{0} =A_{0} e^{-kt} \\0.125A_{0} =A_{0} e^{-k\times0.00140 yr^{-1} }\\ln(0.125)/(-0.00140)=t\\t=504.87 year[/tex]
So, 504.87 yr does it take for the reactant to reach 12.5% of its original value.
Find more information about first- order decomposition reaction here:-
brainly.com/question/20607444
A certain chemical reaction releases of heat for each gram of reactant consumed. How can you calculate the heat produced by the consumption of of reactant? Set the math up. But don't do any of it. Just leave your answer as a math expression. Also, be sure your answer includes all the correct unit symbols.
Complete Question
The complete question is shown in the first uploaded image
Answer:
So the math expression is
[tex]heat = \frac{ 35. 7 KJ * 1900 \ gram }{ 1 \ gram }[/tex]
Explanation:
From the question we are told that
The heat released for 1 gram of reactant consumed is [tex]H = 37.5 \ KJ/g [/tex]
The mass of reactant considered is [tex]m = 1.9 \ kg = 1900 \ g[/tex]
So if
[tex]37.5 \ KJ [/tex] is produced for 1 gram
Then
x kJ is produced for 1900 g
=> [tex]x = \frac{ 35. 7 KJ * 1900 \ gram }{ 1 \ gram }[/tex]
So the heat released is
[tex]heat = \frac{ 35. 7 KJ * 1900 \ gram }{ 1 \ gram }[/tex]
Automobile air bags inflate following a serious impact. The impact triggers the following chemical reaction.
2NaN3(s)->2Na(s)+3N2(g)
If an automobile air bag has a volume of 11.9 L, what mass of NaN3 (in g) is required to fully inflate the air bag upon impact? Assume STP conditions.
Answer:
Explanation:
To determine the molar volume of the gas according to the equation at stp;
1 mole = 22.4 dm³
2 moles = 44.8 dm³
To determine the mass of NaN₃ inflated according to the equation
2NaN₃ (where Na = 23g and N = 14) = (2 × 23) + 2(14 × 3)
= 130 g
Hence, if 130g of NaN₃ is required to inflate 44.8 dm³ airbag upon impact
what mass of NaN₃ is required to fully inflate the air bag upon impact;
130g ⇒ 44.8 dm³
? ⇒ 11.9 dm³ (dm³ is same as L)
? = 130 × 11.9/44.8
? = 34.5g
34.5g of NaN₃ is required to fully inflate 11.9 L of air bag upon impact
What is the value of E0 for the spontaneous reaction resulting from a suitable combination of these half reactions?
Standard Potentials E0
Fe2+ --> Fe3+ + e- -0.77 V
2Hg --> Hg2+ + 2e- -0.79 V
a. +0.02 V.
b. +0.36 V.
c. -1.56 V.
d. -0.02 V.
e. +1.56 V.
Answer:
+0.02 V
Explanation:
For the reaction to be spontaneous, iron must be the cathode and Mercury the anode
Given that the standard cell potential is obtained from;
E°=E° cathode - E° anode
Since;
E° cathode = -0.77V
E° anode = 0.79 V
E°cell = -0.77 -(-0.79)
E°cell = +0.02 V
A piece of metal has a mass of 0.650 kilograms, has a width of 0.136 meters, and has a length of 0.0451 meters.Part A: If the metal’s volume is 291 cm3, what is the height of the metal in centimeters? (The width & length values given above are in a different unit!)
Part B: What is the density of this piece of metal?
Answer:
height = 4.74 cm
density = 2.23 g/ cm³
Explanation:
Mass of metal = 0.650 kg (650 g)
Width = 0.136 m
Length = 0.0451 m
Volume of metal = 291 cm³
Height in cm = ?
density of metal =?
Solution:
Width = 0.136 m (0.136 m×100 cm/1m = 13.6 cm)
Length = 0.0451 m (0.0451 m×100 cm/1m = 4.51 cm)
First of all we will calculate the height:
Volume = height× width× length
291 cm³ = h × 13.6 cm × 4.51 cm
291 cm³ = h × 61.34 cm²
h = 291 cm³ / 61.34 cm²
h = 4.74 cm
Density:
d = m/v
d = 650 g/291 cm³
d = 2.23 g/ cm³
For the combustion of methane presented in Example 5.4, the chemical reaction is CH4 +2O2 →CO2 +2H2O Suppose that methane flows into a burner at 30 gmol/s, while oxygen flows into the same burner at 75 gmol/s. If all the meth- ane is burned and a single output stream leaves the burner, what is the mole fraction of CO2 in that output stream? Hint 1: Does the fact that all the methane is burned mean that all the oxygen is burned also? Hint 2: Find the molar flow rate of each component gas in the outlet gas ("flue gas").
Answer:
[tex]x_{CO_2}^{out} =0.25[/tex]
Explanation:
Hello.
In this case, for the reactive scheme, it is very convenient to write each species' mole balance as shown below:
[tex]CH_4:f_{CH_4}^{out}=f_{CH_4}^{in}-\epsilon \\\\O_2:f_{O_2}^{out}=f_{O_2}^{in}-2\epsilon\\\\CO_2:f_{CO_2}^{out}=\epsilon\\\\H_2O:f_{H_2O}^{out}=2\epsilon[/tex]
Whereas [tex]\epsilon[/tex] accounts for the reaction extent. However, as all the methane is consumed, from the methane balance:
[tex]0=f_{CH_4}^{in}-\epsilon \\\\\epsilon=30gmol/s[/tex]
Thus, we can compute the rest of the outlet mole flows since not all the oxygen is consumed as it is in excess:
[tex]f_{O_2}^{out}=f_{O_2}^{in}-2\epsilon=75gmol/s-2*30gmol/s=15gmol/s\\\\f_{CO_2}^{out}=15gmol/s\\\\f_{H_2O}^{out}=2*15gmol/s=30gmol/s[/tex]
It means that the mole fraction of carbon dioxide in that output is:
[tex]x_{CO_2}^{out}=\frac{15}{15+15+30} =0.25[/tex]
Best regards.
Your task is to create a buffered solution. You are provided with 0.10 M solutions of formic acid and sodium formate. Formic acid has a pKa of 3.75. 2. Create approximately 20 mL of buffer solution with a pH of 4.25.
Answer:
15.2mL of the 0.10M sodium formate solution and 4.8mL of the 0.10M formic acid solution.
Explanation:
To find the pH of a buffer based on the concentration of the acid and conjugate base we must use Henderson-Hasselbalch equation:
pH = pKa + log [A⁻] / [HA]
Where [A⁻] could be taken as moles of the sodium formate and [HA] moles of the formic acid
4.25 = 3.75 + log [A⁻] / [HA]
0.5 = log [A⁻] / [HA]
3.162 = [A⁻] / [HA] (1)
As both solutions are 0.10M and you want to create 20mL of the buffer, the moles are:
0.10M * 20x10⁻³L =
2x10⁻³moles = [A⁻] + [HA] (2)
Replacing (2) in (1):
3.162 = 2x10⁻³moles - [HA] / [HA]
3.162 [HA] = 2x10⁻³moles - [HA]
4.162[HA] = 2x10⁻³moles
[HA] = 4.805x10⁻⁴ moles
[A⁻] = 2x10⁻³moles - 4.805x10⁻⁴ moles = 1.5195x10⁻³moles
That means, to create the buffer you must add:
[A⁻] = 1.5195x10⁻³moles * (1L / 0.10mol) = 0.0152L =
15.2mL of the 0.10M sodium formate solution[HA] = 4.805x10⁻⁴ moles * (1L / 0.10mol) = 0.0048L =
4.8mL of the 0.10M formic acid solutionWhich energy source would be the best source of energy for rescue workers?
List the sources from worst to best.
Combustion Engine
Solar Cell
Nuclear Power Plant
Hydroelectric Power Plant
Human Powered Generator
Wind Turbine
Fuel Burning Power Plant
Answer:
Solar Cell
Explanation:
Claim 1: The sun (solar cells) is the best energy source for the rescue team.
Please I need help with this
Answer: put 45 mm
Explanation:
Lewis based his theory of bonding on? Is this correct
Question: Describe how molecules would
move in a piece of ice.
Answer:
The molecules in the liquid are moving past one another. The hydrogen end of one water molecule is attracted to the oxygen end of another but only for a short time because they are moving. The molecules in ice are further apart than in liquid water. The molecules in ice are in fixed positions but still vibrate.
Explanation:
How do balanced chemical equations thon the
conservation of mass?
They show that the atoms in the products
may be different than the readarts as long
as the mass does not change,
They show that the atoms in the products are
the same as in the reactants, but the number
of atoms must change,
They show that the number of atoms of each
element is the same in the products and
reactants
Answer:
They show that the number of atoms of each element is the same in the products and reactants
Explanation:
Balanced chemical equations show the conservation of mass in that the number of atoms of each element is the same in the products and reactants.
In balancing chemical equation, the idea is to conform with the law of conservation of mass. It states that "during a chemical reaction, atoms are neither created nor destroyed but they simply combine to form new products". In chemical reaction, the atoms are still the same but new compounds ensue. The atoms still maintain their number.Answer:
C (They show that the number of atoms of each element is the same in the products and reactants.)
For the next question: C (2H2(g) + O2(g) → 2H2O(g))
Explanation:
For Edge
What is it called when two or more atoms combine and are held together 2 poin
by a chemical bond
Answer:
Covalent bonds
Explanation:
i'm pretty sure it's fusion but i may be wrong.
Georgia discovered a piece of metal. She measured its mass as 14 grams and its volume as 2 cm3. Georgia then compared the metal she found with the metals in the table below.
DENSITY OF METALS
Which type of metal did Georgia most likely find?
A.Gold
B.Lead
C.Silver
D.Zinc
Answer:
try dividing the grams and the volume and see what number matches up with your answer
Explanation:what is the overall charge of an atom with 17 protons 17 neutrons and 20 electrons
Answer:
Overall charge = -3
Explanation:
The atom of every chemical element is its smallest indivisible part. However, this atom further consists of subatomic particles namely: proton, electron, and neutron. The proton and electron are the positively charged and negatively charged particle respectively.
In a neutral atom, the amount of proton and electrons in that atom equates. However, the amount of electron and proton present in an atom determines the charge of that atom. For example, in this question, an atom is said to contain 17 protons, 17 neutrons and 20 electrons.
Since the negatively charged electrons (20) are more than the positively charged protons (17) by 3, hence, the net charge is -3.
Volume of HCl used 25.0mL 4 l
Initial burette reading 0.50mL
Final burette reading 25.60mL
Concentration of KOH 1.0M
the molarity
HCl solution
Calculate
Answer:
1.0 M
Explanation:
Reaction equation;
KOH(aq) + HCl(aq) -----> KCl(aq) + H2O(l)
Concentration of acid CA = ?
Concentration of base CB = 1.0 M
Volume of base VB = 25.60 - 0.50 = 25.1 ml
Volume of acid VB = 25.0 ml
Number of moles of acid NA = 1
Number of moles of base NB =2
CAVA/CBVB =NA/NB
CAVANB = CBVBNA
CA = CBVBNA/VANB
CA = 1 * 25.1 * 1/25.0 *1
CA = 1.0 M
Which of the following is NOT an example of deposition?
sand dune
river delta
cave crystal
valley
This science btw
Answer:
Cave Crystal
Explanation:
I believe it's cave crystal because sand dunes, river deltas, and valleys are all examples of deposition.
How many sulfur atoms are present in 100 grams of this compound? Report your answer to three significant figures.
Answer:
1.88 × 10²⁴ atoms
Explanation:
Step 1: Given data
Mass of sulfur: 100 g
Step 2: Calculate the moles corresponding to 100 g of sulfur
The molar mass of sulfur is 32.07 g/mol. The moles corresponding to 100 g of sulfur are:
100 g × (1 mol/32.07 g) = 3.12 mol
Step 3: Calculate the number of atoms in 3.12 moles of sulfur
We will use Avogadro's number: there are 6.02 × 10²³ atoms of sulfur in 1 mole of sulfur.
3.12 mol × (6.02 × 10²³ atoms/1 mol) = 1.88 × 10²⁴ atoms
