If you have 3.5 L of He to blow up balloons... at STP...

a) How many moles of He do you have?

b) How many grams of He do you have?

Answers

Answer 1

Answer:

B

Explanation:


Related Questions

The circuit below is powered by a 20-volt battery. What current is flowing through the on/off switch (when it is on, as shown)?

Answers

Answer:

The answer is "0.38 A".

Explanation:

Please find the missing image file in the attachment.

In the given image let:

[tex]R_{12} =R_1+R_2=16 \ \Omega \\\\R_{34} =R_3+R_4=20 \ \Omega \\[/tex]

[tex]R_P=\frac{R_{12} \cdot R_{34}}{R_{12} +R_{34}}[/tex]

     [tex]= \frac{16 \cdot 20 }{16 +20}\\\\= \frac{320 }{36}\\\\= \frac{80 }{9}\\\\= 8.88 \ \Omega[/tex]

similarly,

[tex]R_{eq} =R_p+R_5+R_6\\\\[/tex]

      [tex]=8.88+24+20\\\\=52.89 \ \Omega \\\\[/tex]

calculating the current value through a switch:

[tex]\to I=\frac{V}{R_{eq}} = \frac{20 \ v}{52.89 \Omega }=0.38\ A[/tex]

Answer:

D. 0.38 amperes

Explanation:

Got it correct on Gizmos

Gizmos explanation: This compound circuit contains two parallel branches connected in series to 2 more resistors. Each parallel branch contains 2 resistors in series. The resistance of the first branch is 5+11=16 ohms, and the resistance of the second branch is 20 ohms. Using the equivalent resistance formula, the resistance of this section is

1R=116+120=580+480=980

So R is 809, or 8.89 ohms. This is connected in series to a 24-ohm and a 20-ohm resistor, for a total resistance of 52.89 ohms. The battery voltage is 20 volts, so by Ohm's law

I=VR

I=2052.89=0.38amperes

In the Energy and Specific Heat lab, what temperature should be recorded as the final temperature of the water when measuring the food sample?
A. The temperature of the water when the food sample is first lit
B. The temperature of the water when the food sample has finished burning completely.
C. The highest temperature the water reaches as the sample burns
D. The temperature of the water after the food sample ash has been removed

Answers

Answer:

B. The temperature of the water when the food sample has finished burning completely.

Explanation:

Heat or thermal energy is a form of energy that transfers from one object to another due to a temperature difference between the objects. The units for heat are joules or calories.

Calorimetry is the measurement of heat energy released or absorbed in a chemical  reaction. A calorimeter is used in calorimetry. The calorimeter operates on the Law of Conservation of Energy which states that energy is never created or destroyed but is transformed from one form to another or between objects.

In food calorimetry, the energy released when food is burned is measured by recording the rise in temperature of water in a calorimeter when a given mass of a food sample is burned completely.

Energy can be calculated using the formula: Q = mc ∆T

where Q = the energy in joules or calories, m = the mass in grams, c = specific heat and ∆T = the change in temperature (final temperature - initial temperature).

The temperature of the water when the food sample has finished burning completely is taken as the final temperature of the water. The sample is allowed to smolder for sometime before recording the final  water temperature. This is because the water temperature will continue to rise after the  flame has gone out.

Which statement about Niels Bohr's atomic model is true?
O Higher orbits have lower energies.
O Each orbit has a specific energy level.
O Electrons can exist in any energy level.
O Orbits close to the nucleus have no energy.

Answers

Answer:

O Each orbit has a specific energy level.

Explanation:

Neils Bohr put forward his own model of the atom based on the quantum mechanics originally developed by Planck.

He assumed the Rutherford's model and suggested that the extranuclear part consists of electrons in specific spherical orbits around the nucleus.

The orbits/energy level are the permissible through which the electrons can move through.

His concept is based the concept that the electron can move round the nucleus in certain permissible orbitss

Suppose two students grab an end of a rope. Both shake a rope once in a upward direction to create crests traveling at each other. What would you see when crests meet? What type of interference does this show?

Answers

Answer:

This creates destructive interference.

Explanation:

When the two ends meet they will cancel each other out.

Both students are shaking the rope in the upward direction. Hence their crest will meet up and form the constructive  interference pattern. The intensity of the increases.

What is constructive interference ?

When two waves moves in phase, their crest or troughs add up and the amplitude of the wave increases. This phenomenon is called constructive interference.

If the two waves are passing out of phase to each other then they undergo destructive interference. The amplitude of the destructive interference pattern reduces from their initial values.

Here, both students are shaking the rope in the upward direction. Thus, they are in moving in phase. Hence their crest will meet up and form the constructive  interference pattern. The intensity of the increases.

Find more on interference?

https://brainly.com/question/16098226

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an unknown substance has a mass of 57.4 g and occupies a volume of 34.3 ml. what is the density in g/ml?

Answers

Answer: 1.67

D=M/V

(D=57.4/34.3)= 1.67

6. 7. A hyperbaric chamber has a volume of 200. L. (a) How many moles of oxygen are needed to fill the chamber at room temperature (23°C) and 3.00 atm pressure? b) How many grams of oxygen are needed? (Hint: Since moles have been asked, which equation has the moles listed in the equation. Use that to solve this problem. Also don’t forget to use the equation 1 mole = Formula weight or Molecular weight to calculate the grams of O2).

Answers

Answer:

a) 24.7 mol

b) 790 g

Explanation:

Step 1: Given data

Volume of the chamber (V): 200. LRoom temperature (T): 23 °CPressure of the gas (P): 3.00 atm

Step 2: Convert "T" to Kelvin

We will use the following expression.

K = °C + 273.15

K = 23°C + 273.15 = 296 K

Step 3: Calculate the moles (n) of oxygen

We will use the ideal gas equation.

P × V = n × R × T

n = P × V/R × T

n = 3.00 atm × 200. L/(0.0821 atm.L/mol.K) × 296 K = 24.7 mol

Step 4: Calculate the mass (m) corresponding to 24.7 moles of oxygen

The molar mass (M) of oxygen ga sis 32.00 g/mol. We will calculate the mass of oxygen using the following expression.

m = n × M

m = 24.7 mol × 32.00 g/mol = 790 g

Where and in what features is water found on Earth?

Answers

Answer:  On Earth, liquid water exists on the surface in the form of oceans, lakes and rivers. It also exists below ground as groundwater, in wells and aquifers. Water vapor is most visible as clouds and fog. The frozen part of Earth's hydrosphere is made of ice: glaciers, ice caps and icebergs.

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6. What is the mass, in grams, of 1.92 moles of Ca(OH),?

Answers

Answer:

Mass =  142.25 g

Explanation:

Given data:

Mass of Ca(OH)₂ = ?

Number of moles of Ca(OH)₂ = 1.92 mol

Solution:

Formula:

Mass = number of moles × molar mass

Molar mass of Ca(OH)₂ = 74.09 g/mol

by putting values,

Mass = 1.92 mol × 74.09 g/mol

Mass =  142.25 g

As the temperature of a substance increases, the average___________ energy of the particles also increases, and movement overcomes forces of ________ more easily. As temperature decreases particles move more slowly and the_________ forces between particles dominate.

Answers

Answer:

Kinetic; attraction; attraction.

Explanation:

Kinetic energy can be defined as an energy possessed by an object or body due to its motion.

Mathematically, kinetic energy is given by the formula;

[tex] K.E = \frac{1}{2}MV^{2}[/tex]

Where, K.E represents kinetic energy measured in Joules.

M represents mass measured in kilograms.

V represents velocity measured in metres per seconds square.

Conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.

In the process of heat conduction, thermal energy is usually transferred from fast moving particles to slow moving particles during the collision of these particles. Also, thermal energy is typically transferred between objects that has different degrees of temperature and materials (particles) that are directly in contact with each other but differ in their ability to accept or give up electrons.

Hence, as the temperature of a substance increases, the average kinetic energy of the particles also increases, and movement overcomes forces of attraction more easily. As temperature decreases particles move more slowly and the attraction-forces between particles dominate.

In conclusion, when a substance or an object is heated, a phase change starts to occur only when the average kinetic energy of its particles is great enough to overcome the force of attraction between its particles.

What role do wolves play in the tundra?

Answers

Predator? Not sure if that’s what your looking for.

Answer:

predator

Explanation:

Wolves, arctic foxes, and snowy owls are predators in the tundra.

Set Grouper to 70%. How do you think this level of fishing will affect the populations of the other fish in the simulated reef? Explain your reasoning.

Answers

Answer:

Greatly affect.

Explanation:

This level of fishing will greatly affect the populations of the other fish in the simulated reef because overfishing disturbs the equilibrium in the marine ecosystem. One fish is a food of another fish or the big fish act as a controller which controls the population of other small fishes and in that way the ecosystem is present in equilibrium state so overfishing will greatly affect the marine ecosystem.

which would be a stronger acid H3PO4 or H3PO2​

Answers

Answer:

h3po2

Explanation:

Answer:

i think it is H3PO4

Explanation:

Which of the following BEST describes how these elements would be classified?

A.
Element Q is a nonmetal and element R is a nonmetal.

B.
Element Q is a metal and element R is a metalloid.

C.
Element Q is a nonmetal and element R is a noble gas.

D.
Element Q is a metal and element R is a noble gas.

Answers

The answer is C!! Good luck!

a pressure of 10Nm -2 is equal to ?​

Answers

Answer:

a pressure of 10 Nm -2 is equal to ?​

1 atmosphere

Explanation:

A pressure of 10 N/m² is equal to 10 Pa and 9.86x10⁻⁵ atm.

Pressure (P) is the measure of the perpendicular force (F) applied to an object's surface area (A):

[tex] P = \frac{F}{A} [/tex]                          

Hence, the unit of the pressure is Newton per square meter (N/m²), which is defined as Pascal (Pa).

[tex] 1 Pa = 1 N/m^{2} [/tex]

Also, we have that 1 atm is equal to 101325 Pa, so:

[tex] P = 1 Pa*\frac{1 atm}{101325 Pa} =9.86 \cdot 10^{-6} atm [/tex]

So, in a pressure of 10 N/m² we have:

[tex] P = 10 N/m^{2} = 10 Pa = 9.86 \cdot 10^{-5} atm [/tex]

Therefore, a pressure of 10 N/m² is equal to 10 Pa and 9.86x10⁻⁵ atm.

You can find more about pressure here: https://brainly.com/question/8033367?referrer=searchResults

I hope it helps you!        

6.00 g of a certain Compound X, known to be made of carbon, hydrogen and perhaps oxygen, and to have a molecular molar mass of 26. g/mol, is burned completely in excess oxygen, and the mass of the products carefully measured:
product mass
carbon dioxide 20.31g
water 4.16 g
Use this information to find the molecular formula of X

Answers

Answer:

C2H2

Explanation:

Mass of Carbon in CO2[tex]= (12/44) (20.31)[/tex] grams [tex]= 5.54[/tex] gram

Mass of hydrogen in H2O [tex]= (2/18)(4.26)[/tex] grams [tex]= 0.46[/tex] gram

We will calculate the % of C and H in the sample  

% C [tex]= (5.54/6) * 100 = 92[/tex]%

% H [tex]= (0.46/6)*100 = 7.7[/tex]%

Number of mole of C [tex]= 92/12 = 7.69[/tex]

Number of mole of H [tex]= 7.67/1 = 7.67[/tex]

Fractional share of  C [tex]= 7.69/7.67 = 1[/tex]

Fractional share of  H [tex]= 7.67/7.67 = 1[/tex]

Empirical Formula = CH

Empirical Mass [tex]= 12+1 = 13[/tex]

Molecular mass [tex]= 26[/tex]

Molecular Formula – CHn  

N [tex]= 26/13 = 2[/tex]

Molecular Formula = C2H2

PLZ HELP ASAP WILL GIVE BRAINLIST

2AlCl3 + 2Al + 3Cl2
If 20.0 g of aluminum chloride are decomposed, how many molecules of chlorine gas are produced?
A )6.63 x 1022 molecules CI
B )2.70 x 1023 molecules Cl2
C )1.35 x 1023 molecules Cl2
D )9.42 x 1023 molecules Cl2

Answers

Explanation:

Molar mass of AlCl3 = 133.34g/mol

Moles of AlCl3 used

= 20.0g / (133.34g/mol) = 0.150mol

Mole Ratio of AlCl3 to Cl2 = 2 : 3,

Moles of Cl2 produced

= 0.150mol * (3/2) = 0.225mol

We know that 1 mole of any gas has

6.023 * 10²³ molecules.

Hence, number of molecules in Cl2

= 0.225mol * (6.023 * 10²³/mol)

= 1.35 * 10²³ molecules. (C)

The balanced equation for the production of sugars by photosynthesis is shown below.
This equation demonstrates the law of conservation of mass because
A.
there are more oxygen atoms on the right side of the equation than on the left.
B.
there is the same number of compounds on the right side of the equation as the left.
C.
there is the same number of each type of atom on the right side of the equation as the left.
D.
the sugar molecule on the right has the same mass as the carbon dioxide molecules on the left.

Answers

Answer:

Black

Explanation:

Answer:

the answer is

-there is the same number of each type of atom on the right side of the equation as the left.

Explanation:

i have study island too :')

Which rule states that cracks on glass tend to form at a certain angle on the opposite side of the polnt of Impact?
The
rule states that cracks tend to form at a (n)
angle on the opposite side from the point of Impact.

Answers

Answer:

The 3R rule states that cracks tend to form at a (n) right angle on the opposite side from the point of impact.

Explanation:

Which of the following contains a polyatomic ion?

sodium iodide

carbon monoxide

Iron II oxide

ammonium chloride

Answers

Answer:

i think its oxide not too sure

Answer:  

 Its should be ammonium chloride.

A picture to help you with another question like this

How many cells are a result of Meiosis?

Answers

Answer:

2

Explanation:

Cells divide and reproduce in two ways, mitosis and meiosis. Mitosis results in two identical daughter cells, whereas meiosis results in four sex cells.

Calculate the mass of butane needed to produce 99.0 g of carbon dioxide.
Express your answer to three significant figures and include the appropriate units.

Answers

Answer:

32.7 g

Explanation:

Step 1: Write the balanced combustion reaction

C₄H₁₀ + 6.5 O₂ ⇒ 4 CO₂ + 5 H₂O

Step 2: Calculate the moles corresponding to 99.0 g of CO₂

The molar mass of CO₂ is 44.01 g/mol.

99.0 g × 1 mol/44.01 g = 2.25 mol

Step 3: Calculate the moles of C₄H₁₀ needed to produce 2.25 moles of CO₂

The molar ratio of C₄H₁₀ to CO₂ is 1:4. The moles of C₄H₁₀ needed are 1/4 × 2.25 mol = 0.563 mol.

Step 4: Calculate the mass corresponding to 0.563 moles of C₄H₁₀

The molar mass of C₄H₁₀ is 58.12 g/mol.

0.563 mol × 58.12 g/mol = 32.7 g

A 6.40 g sample of a compound is burned to produce 8.37 g CO_2, 2.75 g H_2O, 1.06 g N_2, and 1.23 g SO_2. What is the empirical formula of the compound? Give your answer in the form C#H#N#O#S# where the number following the element’s symbol corresponds to the subscript in the formula. (Don’t include a 1 subscript explicitly).

Answers

The empirical formula :

C₁₀H₁₆N₄SO₇

Further explanation

Given

6.4 g sample

Required

The empirical formula

Solution

mass C :

= 12/44 x 8.37 g

= 2.28

mass H :

= 2/18 x 2.75 g

= 0.305

mass N = 1.06

mass S :

= 32/64 x 1.23

= 0.615

mass O = 6.4 - (2.28+0.305+1.06+0.615) = 2.14 g

Mol ratio :

= C : H : N : S : O

= 2.28/12 : 0.305/1 : 1.06/14 : 0.615/32 : 2.14/16

= 0.19 : 0.305 : 0.076 : 0.019 : 0.133 divided by 0.019

= 10 : 16 : 4 : 1 : 7

The empirical formula :

C₁₀H₁₆N₄SO₇

3. What determines the frequency (color) of photons?​

Answers

whatever the photon doesn’t absorb (color)

BALANCE THIS CHEMICAL EQUATION PLS, help:)

Answers

Answer:

4C₈H₄OH +  35O₂  →  32CO₂   +   10H₂O  

Explanation:

The unbalanced reaction expression is given as:

     

         C₈H₄OH +  O₂  →  CO₂   +   H₂O  

To solve this problem, we use a mathematical approach.

     aC₈H₄OH +  bO₂  →  cCO₂   +   dH₂O

Conserving C: 8a  = c

                    H:  5a  = 2d

                    O: a + 2b  = 2c + d

Let a  = 1, c  = 8, d  = [tex]\frac{5}{2}[/tex]  , b  = 35

   4C₈H₄OH +  35O₂  →  32CO₂   +   10H₂O  

   

helpppp nowwww plssss!!!

Answers

Answer: B

Explanation:

ANSWER QUICK !!!
How many grams of hydrogen gas will be produced if you start with 15.0 grams of zinc and an excess amount of HCI?

balanced equation:
Zn + 2HCI = ZnCl2 + H2

Answers

Answer:

0.48g

Explanation:

Given parameters:

Mass of zinc  = 15g

Unknown:

Mass of hydrogen gas = ?

Solution:

To solve this problem, we need to state the balanced reaction expression first;

          Zn   +   2HCl   →   ZnCl₂    +   H₂

Find the number of moles of Zn;

    Number of moles  = [tex]\frac{mass}{molar mass}[/tex]    = [tex]\frac{15}{63.4}[/tex]    = 0.24mol

From the balanced reaction expression;

             1 mole of Zn will produce 1 mole of H₂  

            0.24mole of Zn will produce 0.24mole of hydrogen gas

Mass of hydrogen gas  = number of moles x molar mass

                                      = 0.24 x (2 x 1)

                                      = 0.48g

WORTH 40 POINTS HELLPPPP
What class of element is Astatine (At)?

Answers

Answer:

halogen.

nonmetal.

Explanation:

[10 pts]Iron and vanadium both have the BCC crystal structure and V forms a substitutional solid solution in Fe for concentrations up to approximately 20 wt.% V at room temperature. Determine the concentration in weight percent of V that must be added to iron to yield a unit cell edge length of 0.289 nm.

Answers

Answer:

The answer is below

Explanation:

The unit cell edge length (a) = 0.298 nm = 0.289 * 10⁻⁷ cm

The unit volume (V) = a³ = (0.289 * 10⁻⁷ cm)³ = 24 * 10⁻²⁴ cm³

There are 2 atoms per cell, hence N = 2. Also, [tex]n_a=avogadro\ constant=6.02*10^{23}\ mol^{-1}[/tex]

[tex]atomic\ weight\ of\ iron(A_f)=55.85,atomic\ weight\ of\ vanadium(A_V)=50.94,[/tex]

[tex]density\ of\ iron(\rho_f)=7.87,density\ of\ vanadium(\rho_v)=6.1.\\\\V=\frac{nA_{av}}{n_a\rho_{av}} \\\\A_{av}=\frac{100}{C_v/A_v+C_f/A_f} \\\\\rho_{av}=\frac{100}{C_v/\rho_v+C_f/\rho_f} \\\\C_v=concentration\ of\ vanadium,C_f=concentration\ of\ iron.\\\\V=\frac{nA_{av}}{n_a\rho_{av}}=\frac{n*\frac{100}{C_v/A_v+C_f/A_f}}{n_a*\frac{100}{C_v/\rho_v+C_f/\rho_f}}\\\\[/tex]

[tex]24*10^{-24}=\frac{2*\frac{100}{C_v/50.94+C_f/55.85}}{6.02*10^{23}*\frac{100}{C_v/6.1+C_f/7.87}}\\\\7.2=\frac{C_v/6.1+C_f/7.87}{C_v/50.94+C_f/55.85}\ \ \ (1) \\\\Also:\\\\C_v+C_f=100\%\ \ \ (2)\\\\\\solving\ equation\ 1\ and\ 2\ simultaneously\ gives:\\\\C_v=10\% \ and\ C_f=90\%\\\\[/tex]

If the flour mixture is then taken and put into the oven for about 20 minutes, it turns into something very tasty. What kind of change has happened now?

Answers

Answer:

physical change

Explanation:

i got the same question sorry for the late response but that's the answer good luck

which of these is an example of the climate of a region?
A. Dry
B. Foggy
C. Overcast
D. Sunny​

Answers

its dry i think

Explanation:

it might be dry

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