Answer:
a
Explanation:
4Al(s) + 302(g) -> 2Al2O3(s)
How many oxygen atoms are in the product when 4 atoms of solid
aluminum react with 3 molecules of oxygen gas?
Answer:
6 oxygen atoms
Explanation:
when 4 atoms of solid aluminium react with 3 molecules of oxygen gas, 6 oxygen atoms will be in the product
Help please!!
in the lab you react 23 g of potassium iodide with an excess of lead (II) nitrate to form 18 g of lead (II) iodide precipitate. What is the percent yield of your experiment?
A) 28
B) 56
C) 84
D) 98
This value is approximate.
=============================================
Work Shown:
From the periodic table, we are working with these elements
K = PotassiumI = IodinePb = Leadand they form these relevant compounds
Potassium iodide = KILead (ii) iodide = [tex]PbI_2[/tex]Note: the lead (ii) nitrate chemical formula and it's chemical data (eg: atomic mass) doesn't matter so we won't worry about it.
--------------------
Using the periodic table, specifically the atomic mass of each element mentioned, we can find that:
Molar Mass of KI = 166.00277 grams per molMolar Mass of PbI2 = 461.00894 grams per molThey are approximate values based on the average atomic mass.
Those values are handy in calculating the theoretical yield
That theoretical yield is roughly...
[tex]\left(23 \text{ g } KI\right)*\left(\frac{\text{1 mol } KI}{\text{166.00277 g } KI}\right)*\left(\frac{\text{1 mol } PbI_2}{\text{1 mol} KI}\right)*\left(\frac{\text{461.00894 g } PbI_2}{\text{1 mol } PbI_2}\right)\approx 63.8736668 \text{ g } PbI_2[/tex]
So 23 grams of potassium iodide, and the excess amount of lead (ii) nitrate (the amount of this isn't important as long as it exceeds the potassium iodide amount) react together to produce a theoretical yield of about 63.8736668 grams of lead (ii) iodide precipitate.
-----------------------
Despite us calculating the theoretical yield to be 63.8736668 grams, we actually only got 18 grams. We call this the "actual yield".
To get the percent yield, we divide the actual yield over the theoretical yield and multiply by 100%
So,
[tex]\text{percent yield} = \frac{\text{actual yield}}{\text{theoretical yield}}*100\%\\\\\text{percent yield} \approx \frac{18 \text{ g of } PbI_2}{63.8736668 \text{ g of } PbI_2}*100\%\\\\\text{percent yield} \approx \frac{18}{63.8736668}*100\%\\\\\text{percent yield} \approx 0.2818*100\%\\\\\text{percent yield} \approx 28.18\%\\\\\text{percent yield} \approx 28\%\\\\[/tex]
In short, we expected to get a theoretical amount of roughly 63.87 grams of lead (ii) iodide, but instead we got roughly 28% percent of that theoretical amount and got 18 grams of it instead.
indefinite shape, but definite volume
Answer:
A solid has definite volume and shape, a liquid has a definite volume but no definite shape, and a gas has neither a definite volume nor shape. The change from solid to liquid usually does not significantly change the volume of a substance.
Explanation:
Which of these goals of President Truman's "Fair Deal" were met?
A. Providing federal aid to education
B. Getting rid of the Taft-Hartley Act
C. Starting a national health insurance program
D. Expanding Social Security
The goals of President Truman's "Fair Deal" were met is to be considered as the option d. Expanding Social Security.
Reason for Truman's "Fair Deal":Congress has approved Truman's extension of Social Security benefits, due to this it eliminates the national health care idea, that avoid any passing of new civil rights legislation, and failed to tackle concerns with respect to the fair labor practices.
Hence, the option d is correct.
And, the rest of the options are incorrect.
Learn more about health here: https://brainly.com/question/22618986
"Fair Deal" was a proposal given by Harry S. Truman, the president of America. The primary goal of the deal was to expand social security. Thus, option D is correct.
What was the "Fair Deal?""Fair Deal" was proposed by Truman to halt the inflation rate by controlling the economy, increase in the minimum wage structure, reform in agriculture, progressive tax layout, expansion of social security, etc.
Truman's fair deal was not a success and was a failure because of the rise in political conservatism. Social security was related to the national health care idea. Only three of his ideas in the deal were met at the end of the congress session others were a failure.
Therefore, the expansion of social security was met in Truman's "Fair Deal."
Learn more about "Fair Trade" here:
https://brainly.com/question/11801594
#SPJ5
4. What do nutrigenomics and pharmacogenomics have in common?
Answer:
Individual genetic variation
Explanation:
is the common factor on which both pharmacogenomics and nutrigenomics are based.
A bicyclist travels the first 800 m of a trip with a speed of 10 m/s, the next 500 m with an
average speed of 5 m/s and the final 1200 m at a speed of 13 m/s. Find the average speed of
the bicyclist for this trip.
Answer:9.18 m/s
Explanation:
The average speed for the entire trip is found ......total distance/total time. Remember r*t=d, so divide both sides by t and get r = d/t.
So the cyclist went 800+500+1200 m = 2500 m for total distance.
10t =800 leads to t=80 sec
5t=500 leads to t=100 sec
13t = 1200 leads to t = 92.3 sec
total time is 272.3 sec
Average speed for the entire trip is 2500 / 272.3 = 9.18 m/s
what action is a result of gravity in relation to moving tectonics plates
Answer:
When the denser tectonic plate dives beneath another plate it is due to the high energy by the Earth’s gravity that pushes into the mantle. Earth’s tides, which are caused by a gravitational tug of the Moon and the Sun, also put extra strain on geological faults. how to prepare for an earthquake
Explanation:
A small block of solid aluminum is removed from a freezer and heated from -5C to 5C in 5 minutes using a hot plate. The hot plate provides a constant rate of heat output during this time.
In a chemical reaction which cannot occur:
Select one:
a. new elements are formed
b. heat is released
c. light is produced
d. a temperature change
Explanation:
Light can't get produced whilst a chemical reaction.
name two life processes that viruses cannot carry out
Two life processes that viruses cannot carry out are Respiration and Sensitivity.
What is the standard enthalpy of a reaction for which the equilibrium constant is (a) doubled, (b) halved when the temperature is increased by 15 K at 310 K
Answer:
a) 48KJ
b) -48KJ
Explanation:
Given that;
ln(K2/K1) = ΔH°/R(1/T2 - 1/T1)
K2= equilibrium constant at T2
K1 = equilibrum constant at T1
R = gas constant
T1 = initial temperature
T2 = final temperature
When we double the equilibrium constant K1; K2 = 2K1
T1 = 310 K
T2 = 310 + 15 = 325 K
ln(2K1/K1) =- ΔH°/R(1/T2 - 1/T1)
ln2 = -ΔH°/8.314(1/325 - 1/310)
0.693 = -ΔH°/8.314(3.08 * 10^-3 - 3.2 * 10^-3)
0.693 = -ΔH°/8.314 (-0.00012)
0.693 = 0.00012ΔH°/8.314
0.693 * 8.314 = 0.00012ΔH°
ΔH° = 0.693 * 8.314/0.00012
ΔH° = 48KJ
b) K2 =K1/2
ln(K1/2/K1) =- ΔH°/R(1/T2 - 1/T1)
ln (1/2) = -ΔH°/8.314 (1/325 - 1/310)
-0.693 = -ΔH°/8.314 (-0.00012)
-0.693 = 0.00012ΔH°/8.314
-0.693 * 8.314 = 0.00012ΔH°
ΔH°= -0.693 * 8.314/0.00012
ΔH°= -48KJ
What information does the potential energy diagram reveal about a reaction?
Answer: The energy changes that occur during a chemical reaction can be shown in a diagram called a potential energy diagram, or sometimes called a reaction progress curve. A potential energy diagram shows the change in potential energy of a system as reactants are converted into products.
Explanation:
Answer:
It shows whether the reaction is exothermic or endothermic.
Explanation:
Look at the food web below.
grass
wheat
grasshopper
mouse
toad
snake
hawk
Which organisms would be at the bottom of the energy pyramid for this
ecosystem?
Explanation:
At the bottom of the energy pyramid, there would be the producers.
In here the producers are grass and wheat. (D)
Which type of radiological technology is useful for viewing tumors?
Answer:
CT Scan
Explanation:
Radiology is a branch of medicine that uses imaging technology to diagnose and treat disease. So, an example of a radiology technology that is useful for viewing tumors is Computed Tomography (CT)Scan. Others include Magnetic resonance imaging (MRI), X-rays etc.
What is the momentum of a bird with a mass of 2 kg flying at 9 m/s? *
Answer:
18 kg.m/sExplanation:
The momentum of an object can be found by using the formula
momentum = mass × velocity
From the question we have
momentum = 2 × 9
We have the final answer as
18 kg.m/sHope this helps you
what kind (ionic or covalent) bond is FeCl2 + Na2CO3? (iron (II) chloride + sodium carbonate).
Answer:
corbonate
Explanation:
i think so. not sure
What is the total pressure in units of kPa in a 7.85 L container that contains 4.45 moles of N2 and 2.45 moles of O2 at a temperature of 307 K?
Answer:
32.42
Explanation:
fda
Is CO a acidic
or basic
oxide and why
Answer:
Carbon monoxide is generally treated as though it was a neutral oxide, however truth be told it is extremely, somewhat acidic. It doesn't respond with water, yet it will respond with hot concentrated sodium hydroxide answer for give an answer of sodium methanoate.
Explanation:
To separate a mixture of large gravel and sand, the most effective method would be
Answer:
Sieve
Explanation:
A sieve or screen would be the best tool to use when separating a mixture of sand and gravel.
Answer:
the third option on edge:)
Explanation:
what happens after we die? spirtually and physically
PLEASE ANSWER 10 POINTS PLUS BRAINLIEST IF RIGHT
How did scientists calculate the most exact value for the mole?
1. through x-ray diffraction of silicon atoms
2. through the kinetic molecular theory by calculating the number of particles in a sample of gas
3. through counting the atoms in a sample of carbon-12 under a microscope
4. through the charge of an electron and Faraday’s constant
Answer:
it's answer is through the charge of an electron and Faraday's constant
Which of the following orbits the nucleus?
Select one:
a. proton
b. neutron
c. electron
Answer:
Electrons are the orbiting particles
Explanation:
Hope this helps UvU
Can someone please walk me through this?-- 25 pts!
Calculate the change of enthalpy for the reaction CH4 (g) + NH3 (g) --> HCN (g) +3H2 (g) from the following reactions:
Reaction 1: N2 (g) + 3H2 (g) --> 2NH3 (g); Change in enthalpy(∆ H): -91.8 kJ/mol
Reaction 2: C (s, graphite) + 2H2 (g) --> CH4 (g); Change in enthalpy(∆ H): -74.9 kJ/mol
Reaction 3: H2 (g) + 2C (s, graphite) + N2 (g) --> 2HCN (g); Change in enthalpy(∆ H): +270.3 kJ/mol
I have to include the following:
>The numerical answer with correct units.
>State which reactions, if any, you had to "Flip". ("Flipping" refers to modifying one of the reactions above to make a chemical be present on the other side-- like flipping an N2 that is on the reaction side. If it needs to be on the product side, you flip the reaction. Hope that makes sense.)
>State which reactions you had to multiply, if any, to get the correct amount of the compound. Also, include how much you multiplied the reaction by.
NH3(g) + CH4(g) ⇒ HCN + 3H2 ∆ H:255.95
Further explanationGiven
Reaction and the enthalpy
Required
The change of enthalpy
Solution
Reaction 1
N2 (g) + 3H2 (g) --> 2NH3 ∆ H: -91.8 kJ/mol⇒reverse
2NH3 ⇒ N2 (g) + 3H2 (g) ∆ H: +91.8 kJ/mol
Reaction 2
C (s, graphite) + 2H2 (g)⇒ CH4 (g) ∆H: -74.9 kJ/mol ⇒reverse
CH4 (g) ⇒ C (s, graphite) + 2H2 (g) ∆H: +74.9 kJ/mol ⇒ x2
2CH4 (g) ⇒ 2C (s, graphite) + 4H2 (g) ∆H: +149.8 kJ/mo
Reaction 3
H2 (g) + 2C (s, graphite) + N2 (g) ⇒ 2HCN (g);∆ H: +270.3 kJ/mol
Add up all the reactions and remove the same compound from different sides :
2NH3 ⇒ N2 (g) + 3H2 (g) ∆ H: +91.8 kJ/mol
2CH4 (g) ⇒ 2C (s, graphite) + 4H2 (g) ∆H: +149.8 kJ/mol
H2 (g) + 2C (s, graphite) + N2 (g) ⇒ 2HCN (g) ∆ H: +270.3 kJ/mol
-----------------------------------------------------------------------------------------
2NH3(g) + 2CH4(g) ⇒ 2HCN + 6H2 ∆ H: 511.9 ⇒ :2
NH3(g) + CH4(g) ⇒ HCN + 3H2 ∆ H:255.95
A sample of water is heated from 10 °C to 50 °C using 286 J of energy. What is the mass of water that was heated? help
Answer:
Mass of water == 1.71 g
Explanation:
Given data:
Initial temperature of water = 10°C
Final temperature of water = 50°C
Energy absorbed = 286 J
Mass of water = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Specific heat capacity of water is 4.18 J/g.°C
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 50°C - 10°C
ΔT = 40°C
by putting values,
286 J = m × 4.18 J/g.°C × 40°C
286 J = m × 167.2 J/g
m = 286 J / 167.2 J/g
m = 1.71 g
The images show two different fronts. Item A: A cold front and warm front meet with high level, grey clouds. Item B: Warm air is above cold and very cold air, lower clouds with rain falling. Which fronts are shown? Item A shows a cold front, and item B shows a warm front. Item A shows an occluded front, and item B shows a cold front. Item A shows a warm front, and item B shows a stationary front. Item A shows a stationary front, and item B shows an occluded front.
Answer:
d
Explanation:
because it cause the weather it moves
Answer:
D is the answer ( not 100% sure tho )
Which of the alkaline-earth metals has the smallest ionization energy?
Answer:
Cesium
Explanation:
Which of the following issues do you think is most important when addressing food problems on a global scale?
Political instability in third-world countries
The need for exotic spices to make foods taste better
Removing chemicals from pesticides that could be harmful to the environment
Rising global temperatures that intensify droughts
Producing foods that use less land and feed more people
Ensuring humane and healthy treatment of farm animals
Answer:
Removing chemicals from pesticides that could be harmful to the environment
Explanation:
This is a main food issue that is not only state-wide but global
1st option doesn't say anything about food issues which makes it unnecessary to address
2nd option is a suggestion and not necessary
4th option is again not exactly towards food issues so no need to address for this question
5th option isn't a issue as much as just something we could do for convenience and stability
6th option should already be in act and is unlawful to do which leads me to the correct option
3rd option is correct because it is still okay globally to put chemicals into our food to keep it looking better for longer amounts of time. Yet it is dangerous to us living beings and the environment.
So therefore 3rd option is correct
(have a great day!)
H2O2 → H2O + O2 as a balanced equation
Answer:
2H2O2 → O2 + 2H2O
Explanation:
2H2O2
H : 2x2= 4
O : 2x2=4
O2 + 2H2O
H : 2x2=4
O : 2+2=4
First, be sure to count all of H and O atoms on each side of the chemical equation. Once you know how many of each type of atom you have you can only change the coefficients (the numbers in front of atoms or compounds) in order to balance the equation.
A family consumes 2.5 gallons of milk per week. How many liters of milk do they need to buy for one month? (Assume there are exactly 4 weeks in 1 month) SHOW WORK
Answer:
37.85 liters
Explanation:
they need 10 gallons for a month (2.5*4)
after that, convert gallons to liters (conversion to liters= 3.785)
10*3.7585= 37.85
Squeeze out juice from an unripe orange. Put tiny piece of Zinc or Aluminum foil into the juice. Leave the mixture for a few minutes. State and explain your observation.
Answer:
A colorless odorless gas evolves
Explanation:
Orange juice is highly acidic. Unripe orange juice is even more acidic! As a result of this, unripe orange juice irritate the digestive tract.
We know that metals that are high up in the activity series evolves hydrogen gas when in contact with acids.
Hence, given the low pH of unripe orange juice, zinc or aluminium will evolve colorless odorless hydrogen gas after some minutes.