2
Which group of substances contains only compounds?
A C, O2, CH4,
B H, He, F
C CO2, CaCO3 , CH4
D F, Fe, He
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Answer:

d. add another d-cell to the circuit

Explanation:

To make the electromagnet pick something, the student should add another d-cell to the circuit.

Simply, the electromagnet set up is generating very weak magnetic fields.

Answer:

Number of moles of oxygen = 0.037  mol

Explanation:

Given data:

Total pressure = 98.5 KPa

Partial pressure of nitrogen = 22.0 KPa

Partial pressure of argon = 50.0 KPa

Volume = 3.5 L

Temperature = 25°C (25+273= 298K)

Number of moles of oxygen = ?

Solution:

Total pressure = P(N₂) + P(O₂) + P(Ar)

98.5 KPa = 22.0 KPa +P(O₂) + 50.0 KPa

98.5 KPa = 72.0 KPa +P(O₂)

P(O₂)  = 98.5 KPa - 72.0 KPa

P(O₂)  = 26.5 KPa

KPa to atm:

26.5 KPa/ 101 = 0.262 atm

Number of moles of oxygen:

PV = nRT

n = PV/RT

n = 0.262 atm × 3.5 L / 0.0821 atm.L/mol.K  × 298 K

n = 0.917atm.L /24.47atm.L/ mol

n = 0.037  mol

Answer:

520ML and apparently I need to put more in this answer

Explanation:

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Answer:

tell how you feel

Explanation:

don't be afraid to express your feeling.  

Answer:

slowly approach them and tell your feelings

Answer:

the answer is B  Equals i just took the test

Answer:

See explanation

Explanation:

The work function is given by;

Wo = hc/λ

where;

h = 6.6 * 10^-34 Js

c = 3 * 10^8 ms-1

λ = 281 nm or 281  * 10^-9 m

Wo = 6.6 * 10^-34 * 3 * 10^8 /  281  * 10^-9

Wo = 7.0 * 10^-19 J or 4.375 eV

Note that the work function is the minimum energy required to eject an electron from a sample of tin.

Answer:

A typical range of ATOMIC radii would be 0.050 − 0.200 nm or so.

Answer:

Cs > Iron > Aluminum > Carbon > Neon

Explanation:

The most metallic from the given choices is Cesium and the least metallic is Neon.

Neon is noble gas and not a solid.

Metallic character of elements decreases across the period and increases with increasing electronegativity.

The most leftward element is Cesium and will be the most metallic. Neon has the least metallic character since it is a noble gas.

    Cesium > Iron > Aluminum > Carbon > Neon

Answer:

Explanation:

1. A measure of how quickly velocity is changing is the acceleration

Acceleration is the rate of change of velocity with time. The rate at which a body is changing its velocity is known as the acceleration.

It is measured in the unit m/s²

2. Speed in a given direction is the velocity

Velocity is a vector quantity which measures the magnitude of motion in a specific direction. It is simply speed in a given direction.

When we say a motorcycle travels at the rate of 5m/s due east, we are describing the velocity of such body.

3. Force that resists moving one object against another is the friction

Friction is a force that opposes motion. It prevents a body from moving.

4. Measure of the pull of gravity on an object Weight

Weight is a measure of the amount of gravitational force on a body. It is mathematically expressed as;

         W = mg

W is the weight, m is the mass and g is the acceleration due to gravity

5 Tendency of an object to resist a change in motion is inertia

Inertia is the tendency of body to resist change in motion. It is the ability of a body to remain in a perpetual state of rest.

6 Size is the magnitude

Answer:

It’s A

Explanation:

Got it right on edge just wanted to give the simple answer

Answer:

A. It will probably snow today.

Answer:

avada kadvera

Explanation:

what comes around goes around

Answer:

ok

Explanation:

Answer:

Hi

Explanation:

Good morning, thx for the free points, have a great day/night, and stay safe!

Answer:

0.00726mol

Explanation:

Using general gas equation,

PV = nRT

Where;

P = pressure

V = volume

n = number of moles

R = gas constant (0.0821 L atm mol/K)

T = temperature

First, we need to convert the units of each variable

Volume = 185mL = 0.185L

Pressure = 760.0 torr = 1 atm

Temperature = 98.6°F = 310.15K

PV = nRT

1 × 0.185 = n × 0.0821 × 310.15

0.185 = 25.46n

n = 0.185/25.46

n = 0.00726mol

Answer:

Mass of calcium chloride produced = 24.14 g

Explanation:

Given data:

Mass of ammonia produced = 7.4 g

Mass of calcium chloride produced = ?

Solution:

Chemical equation:

2NH₄Cl + CaO      →   2NH₃ + H₂O + CaCl₂

Number of moles of ammonia produced:

Number of moles = mass/molar mass

Number of moles = 7.4 g/ 17 g/mol

Number of moles =  0.435 mol

Now we will compare the moles of ammonia and calcium chloride.

             NH₃          :         CaCl₂

              2              :              1

          0.435          :         1/2×0.435 = 0.2175 mol

Mass of calcium chloride produced:

Mass = number of moles × molar mass

Mass = 0.2175 mol ×110.98 g/mol

Mass = 24.14 g

Answer:

D

Explanation:

Because it has the highest number

A THE ANSWER IS A  

U WELCONM

Answer:

COLORS

Explanation:

i looked it up lol

answer: spectrum

explanation: your eyes see different wavelengths of light as different spectrum.

hope it helps sis

Answer:

Elements in the same period have the same number of atomic orbitals.

Explanation:

The number of orbitals depends on the row. (E.g. all elements in the top row have the same number of atomic orbitals: 1. All elements in the second row have 2 atomic orbitals for their electrons.)

Answer:

4.08 x 10^-8

Explanation:

Answer:

17.38 meters per second

Explanation:

Speed is distance over time so 112.6 / 1.8 hours =62.5555555556 km per hour. TO find it in m/s just divide 62.5555555556 by 3.6 and that is approximately equal to 17.38 meters per second, or at least something close to it.

Please mark brainliest!!! Thanks.

The four spheres are closely related, and continuously interact.

The earth is divided into four spheres;

Matter cycles through all these four spheres of the earth via the diverse biogeochemical cycles that exist in nature such as oxygen cycle, carbon cycle, nitrogen cycle etc. Most of these cycles have components in all the four earth spheres.

Therefore, the four spheres are closely related, and continuously interact.

Learn more: https://brainly.com/question/24092645

Answer:

V  = 131.23 L

Explanation:

Given data:

Moles of CO₂ = 5.3 mol

Temperature = 28°C

Pressure = 0.998 atm

Volume occupied = ?

Solution:

Formula:

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K  

T = temperature in kelvin

Now we will convert the temperature.

28+273 = 301 K

0.998 atm ×V = 5.3 mol × 0.0821 atm.L/ mol.K  × 301 K

V = 130.97 atm.L / 0.998 atm

V  = 131.23 L

Mass of element P = 1.44 g

Proust stated the Comparative Law that compounds are formed from elements with the same Mass Comparison so that the compound has a fixed composition of elements

In the same compound, although from different sources and formed by different processes, it will still have the same composition/comparison

MW Q₂P₃ = 2.27 + 3.16=102 g/mol

Mass Q₂P₃ (MW=102 g/mol) :

[tex]\tt mass~Q_2P_3=\dfrac{MW~Q_2P_3}{2.Ar~Q}\times mass Q\\\\mass~Q_2P_3=\dfrac{102}{2\times 27}\times 1.62\\\\mass~Q_2P_3=3.06~g[/tex]

Mass P (Ar=16) :

[tex]\tt mass~P=\dfrac{3.Ar~P}{MW~Q_2P_3}\times mass~Q_2P_3\\\\mass~P=\dfrac{3.16}{102}\times 3.06\\\\mass~P=1.44~g[/tex]

or you can solve it with mol :

Reaction

3P + 2Q ⇒ Q₂P₃

mol Q :

[tex]\tt \dfrac{1.62}{27}=0.06[/tex]

mol P :

[tex]\tt \dfrac{3}{2}\times 0.06=0.09[/tex]

mass P :

[tex]\tt 0.09\times 16=\boxed{\bold{1.44~g}}[/tex]

Answer:

The percent isotopic abundance of Ir-193 is 60.85 %

The percent isotopic abundance of Ir-191 is 39.15 %

Explanation:

we know there are two naturally occurring isotopes of iridium, Ir-191 and Ir-193

First of all we will set the fraction for both isotopes

X for the isotopes having mass 193

1-x for isotopes having mass 191

The average atomic mass is 192.217

we will use the following equation,

193x + 191(1-x) = 192.217

193x + 191 - 191x = 192.217

193x- 191x = 192.217 - 191

2x = 1.217

x= 1.217/2

x= 0.6085

0.6085 × 100 = 60.85 %

60.85% is abundance of Ir-193 because we solve the fraction x.

now we will calculate the abundance of Ir-191.

(1-x)

1-0.6085 =0.3915

0.3915× 100= 39.15 %

The pressure of the CO₂ = 0.995 atm

The complete question

A student is doing experiments with CO2(g). Originally, a sample of gas is in a rigid container at 299K and 0.70 atm. The student increases the temperature of the CO2(g) in the container to 425K.

Calculate the pressure of the CO₂ (g) in the container at 425 K.

Gay Lussac's Law

When the volume is not changed, the gas pressure is proportional to its absolute temperature

[tex]\tt \dfrac{P_1}{T_1}=\dfrac{P_2}{T_2}[/tex]

P₁=0.7 atm

T₁=299 K

T₂=425 K

[tex]\tt P_2=\dfrac{P_1\times T_2}{T_1}\\\\P_2=\dfrac{0.7\times 425}{299}=0.995 `atm[/tex]

Answer:

Volume of gas when release form tank = V₂ = 2026.67 L

Explanation:

Given data:

Initial volume of gas =V₁= 10.0 L

Pressure of gas inside tank =P₁= 30400 mmHg

Volume of gas when release form tank =V₂=  ?

Pressure at peak =P₂= 150 mmHg

Solution:

The given problem will be solved through the Boly's law,

"The volume of given amount of gas is inversely proportional to its pressure by keeping the temperature and number of moles constant"

Mathematical expression:

P₁V₁ = P₂V₂

P₁ = Initial pressure

V₁ = initial volume

P₂ = final pressure

V₂ = final volume  

Now we will put the values in formula,

P₁V₁ = P₂V₂

30400 mmHg × 10.0 L =  150 mmHg × V₂

V₂ = 304000 mmHg. L/  150 mmHg

V₂ = 2026.67 L

The rollercoaster has a speed of 176 ft/sec. This can be converted to miles per hour. The speed is equivalent to 120 mph.

Speed is a physical quantity measuring the distance travelled by an object per unit time. Speed is a scalar quantity. The rate of speed is called velocity.

The speed can be expressed in different units. such as m/s, km/h, ft./s miles per hour etc. These units can be interconverted using specific relations.

One ft/s = 0.682 mph

then, 176 ft./s  = 0.682 × 176 = 120 mph.

Therefore, the speed of the roller coaster is 120 mph.

Find more on speed:

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