Help me please I really need this tomorrow

Help Me Please I Really Need This Tomorrow

Answers

Answer 1

Answer:

answers:

1.b

2.d

3.b

4. c

5.c

6.d

7.c

Explanation:

I think this is the correct answer pls mark brainliest and like..

Answer 2

19. place moth balls in the closet and observe after several days.

20. whenever wax or a candle burns it turns from solid to liquid but again at room temperature it turns to solid

21. evaporation, condensation, precipitation

22. it produces new substances

23. vinegar Bubbles when baking soda is added.

24. steam


Related Questions

A sample of helium has a temperature of 450 K. The gas is cooled to 248.9 K at which time the gas occupies 103.4 L? Assume pressure is constant at 3 atm. What was the original volume of the gas?

A. 186.94 L
B. 304.5 L
C. 57.19 L
D. 361.07 L

Answers

Answer:

[tex]\boxed {\boxed {\sf A. \ 186.94 \ L}}[/tex]

Explanation:

We are asked to find the original volume of a gas given a change in temperature. Since pressure remains constant, we are only concerned with volume and temperature, so we use Charles's Law. This states the volume of a gas is directly proportional to the temperature. The formula for this law is:

[tex]\frac {V_1}{T_1}= \frac{V_2}{T_2}[/tex]

The gas begins with a temperature of 450 Kelvin, but the volume is unknown.

[tex]\frac {V_1}{450 \ K }= \frac{V_2}{T_2}[/tex]

The gas is cooled to 248.9 Kelvin and the gas occupies a volume of 103.4 liters.

[tex]\frac {V_1}{450 \ K }= \frac{103.4 \ L}{248.9 \ K}[/tex]

Since we are solving for the original volume, we must isolate the variable V₁. It is being divided by 450 Kelvin. The inverse operation of division is multiplication, so we multiply both sides of the equation by 450 K.

[tex]450 \ K \frac {V_1}{450 \ K }= \frac{103.4 \ L}{248.9 \ K}* 450 \ K[/tex]

[tex]V_1= \frac{103.4 \ L}{248.9 \ K}* 450 \ K[/tex]

The units of Kelvin cancel.

[tex]V_1= \frac{103.4 \ L}{248.9 }* 450[/tex]

[tex]V_1= 0.4154278827 \ L *450[/tex]

[tex]V_1= 186.9425472 \ L[/tex]

Round to the nearest hundredth. The 2 in the thousandths place tells us to leave the 4 in the hundredth place.

[tex]V_1 \approx 186.94 \ L[/tex]

The original volume is approximately 186.94 liters and Choice A is correct.

The volume of a gas was 48 mL when the temperature was 159.6 ºC. If the temperature was initially 4.9 ºC, and there was no change in the pressure, what was the initial volume of the gas?

Answers

V1=48mLT1=159.6°CT2=4.9°CV2=?

According to Charles law

[tex]\boxed{\sf \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}}[/tex]

[tex]\\ \sf\longmapsto \dfrac{48}{159.6}=\dfrac{V_2}{4.9}[/tex]

[tex]\\ \sf\longmapsto V_2=\dfrac{48\times 4.9}{159.6}[/tex]

[tex]\\ \sf\longmapsto V_2=\dfrac{235.2}{159.6}[/tex]

[tex]\\ \sf\longmapsto V_2=1.4mL[/tex]

cho 3,8g hỗn hợp na2co3 và nahco3 tác dụng với dung dịch hcl.Thoát ra 896 khí ở đktc a/ tính thành phần % theo khối lượng mỗi muối trong hỗn hợp đều.b/ tính thể tích dung dịch hcl 20% biết d= 1,1g trên ml​

Answers

Answer:

99

Explanation:

it is matter so it and it has.bein 99

Describe how a constant volume calorimeter can be used to measure the heat transferred from a burning piece of coal to cool water.
thank you <3

Answers

Answer:

A Calorimeter is a device used to measure the amount of heat involved in a chemical or physical process.

Explanation:

Ex- when an exothermic reaction ( accompanied by or requiring absorption of heat)occurs in solution in a calorimeter, the heat produced by the reaction is absorbed by the solution increasing its temperature.

   - When an endothermic reaction (Heat evolving reaction) occurs, the heat required is absorbed from the thermal energy of the solution, decreasing its temperature.

A burning piece of coal which is releasing heat due to its combustion and is transferred to water.

Mark as Brainliest ;)

What is the difference between a strong base and a weak base?
A. A strong base is always more concentrated than a weak base,
B. A strong base has a lower Ki than a weak base.
C. A strong base produces more ions in solution than a weak base,
D. A strong base is not as conductive as a weak base.

Answers

Answer:

C

Explanation:

Compare and contrast qualitative and quantitative data.

Answers

Answer: Qualitative data typically consists of words while quantitative data consists of numbers.

Explanation:

Define physical and chemical properties, provide three examples of each, discuss their reversibility, and explain the fundamental differences between them.

Answers

Answer:

Physical properties are defined as the properties which can be observed without changing their chemical composition.

For example, color, volume, and molecular weight.

Chemical properties can be defined as, a properties that can be seen only after changing the substance's chemical identity.

For example, reactivity, toxicity, and flammability.

The fundamental differences between physical and chemical properties are as follows:

Chemical properties are related to chemical bonds of the substance, while physical properties are not.

In chemical properties, the chemical identity of substance changes while physical properties does not have any change.

Chemical properties predict the reaction of a substance, while physical properties only describe the appearance of the substance.

   

Explanation:

A fixed mass of gas has a volume of 92 cm cube and 3 degrees Celsius. What will be its volume at 18 degrees celsius if the pressure remains constant?​

Answers

Answer:

94.8454

Explanation:

Let volume be V

Let Temperature be T

V1= 92

T1= 3C but to kelvin 273+3= 300K

V2= ?

T2= 18 C but to kelvin 18+273= 291

[tex] \frac{v1}{t1} = \frac{v2}{t2} [/tex]

[tex] \frac{92}{300} = \frac{v2}{291} [/tex]

[tex]v2 \times 300 = 92 \times 291[/tex]

[tex]v2 = \frac{92 \times 291}{300} [/tex]

[tex]v2 = 94.8454[/tex]

Determine the mass of oxygen in a 45.0 g sample of calcium carbonate

Answers

Answer:

The mass of oxygen in 45.0 g sample of calcium carbonate is approximately 21.58 g

Explanation:

The chemical formula for calcium carbonate is CaCO₃

The molar mass of CaCO₃ = 100.0869 g/mol

The mass of oxygen in one mole of CaCO₃ = 3 × 15.999 g = 47.997 g

The mass of oxygen in 45.0 g sample of CaCO₃, m, is goven as follows;

m = 45.0/100.0869 × 47.997 g ≈ 21.58 g

The mass of oxygen in 45.0 g sample of calcium carbonate, m ≈ 21.58 g

Which of the following has maximum number of atoms?
(a) 18 g of H2O
(b) 18 g of O2
(c) 18 g of CO2
(d) 18 g of CO4​

Answers

Answer:

(a) 18 g of H2O

Explanation:

The molecule with great number of moles will have great number of atoms.

By observation, since all compounds have same mass, water has the least molcular mass

[tex]H_{2} O = \: 18 \: g[/tex]

Answer:

18g of H2O

Explanation:

the molecule with great number of moles will have great number of atoms .

(a) option is correct

Which of the following type of matter has weakest interparticle force of attraction O a. Liquid water
O b. Iron
O c. Steam
O d. sand ​

Answers

Answer:(b)liquid water is correct option . Because it is a molecular solid and molecular solid has weak interparticle forces of attraction

Explanation:

which statement best describes a chemical property of a mineral

Answers

Answer:

The mineral forms gas bubbles when a sample is stored in water

Which of the following is an example of a chemical change?
A. Sugar breaking down into water and carbon when it is heated
B. A sugar cube being crushed by a spoon
C. Sugar mixing with red food coloring and forming a red solid
D. A sugar cube dissolving in water as the water is stirred

Answers

Answer:

I think its sugar breaking down into watee and carbon when it is heated

I HOPE ITS RIGHT IF NOT THEN SORRY

HAVE A GREAT DAY :)

Balance the redox reaction by oxidation number or ion electron method and indicate oxidizing and reducing agent . KMno4 + KBr + H2SO4 approach K2SO4 + MnSO4 + H2O + Br2​

Answers

Answer:

2KMnO₄ (aq) + 10KBr (aq) + 8H₂SO₄ (aq) -> 2MnSO₄ (aq) + 5Br₂ (aq) + 6K₂SO₄ (aq) + 8H₂O (l)

oxidizing agent = KMnO₄

reducing agent = KBr

Explanation:

KMnO₄ -> 2Mn + 10e = 2Mn²

KBr -> 10Br - 10e = 10Br

What are the units of molar mass?
A. L/g
B. mol/g
C. g/L
D. g/mol
SUBST

Answers

Answer:

D - g/mol

step by step method

D
I think its the best answer

Infrared waves are an example of heat transfer by
A. convection
B. radiation
C. conduction
D. motion of the air

Answers

Answer:

convection is my correct answer

Determinar el volumen de 20 kg de benceno si su densidad es de 0,88g/cm3

Answers

Answer:

volume = mass/ densidad

0.88g/cm3 = 880kg/m3

v=20kg/880kg/m3

v=0.02272727272

o puede ser 0.0227

o tambien puede ser 0.023

solution is an example of______mixtures​

Answers

Answer:

homogeneous mixture must be the answer

What is the pressure of 4 moles of helium in a 50 L tank at 308 K?
Use PV = nRT.
A. 24.64 atm
B. 0.13 atm
O C. 0.51 atm
D. 2.02 atm

Answers

Answer:

D

Explanation:

P = Pressure

V = Volume

n = Moles

R = .08206 (because we're using liters)

T = Temperature (as K)

P(50) = (4)(.08206)(308)

P(50) = 101.09792

Divide both sides by 50

P(50)/50 = 101.09792/50

P = 2.0219584

Answer:

[tex]\boxed {\boxed {\sf D. \ 2.02 \ atm}}[/tex]

Explanation:

We are asked to find the pressure of helium gas using the ideal gas law.

[tex]PV= nRT[/tex]

In this formula P is the pressure, V is the volume, n is the number of moles of gas, R is the universal gas constant, and T is the temperature.

The pressure is unknown and we are solving for it. The volume is 50 liters, there are 4 moles of helium gas, the universal gas constant is 0.08206 L *atm/ mol * K, and the temperature is 308 Kelvin.

[tex]\bullet \ V= 50 \ L \\\bullet \ n= 4 \ mol \\\bullet \ R = \frac {0.08206 \ L * atm}{mol *K}\\\bullet \ T= 308 \ K[/tex]

Substitute these values into the formula.

[tex]P * 50 \ L= 4 \ mol * \frac {0.08206 \ L * atm}{mol *K} * 308 \ K[/tex]

Multiply on the right side. The units of moles (mol)  and Kelvin (K) cancel each other out.

[tex]P* 50 \ L = 4 * 0.08206 \ L *atm * 308[/tex]

[tex]P*50 \ L =0.32824 \ L * atm *308[/tex]

[tex]P* 50 \ L = 101.09792 \ L * atm[/tex]

We are solving for the pressure, so we must isolate the variable P. It is being multiplied by 50 liters. The inverse operation of multiplication is division, so divide both sides by 50 L.

[tex]\frac {P* 50 \ L}{50 \ L} = \frac {101.09792 \ L * atm}{50 \ L}[/tex]

[tex]P= \frac {101.09792 \ L * atm}{50 \ L}[/tex]

The units of liters (L) cancel.

[tex]P= \frac{101.09792}{50 } \ atm[/tex]

[tex]P= 2.0219584 \ atm[/tex]

If we round to the nearest hundredth place the 1 in the thousandth place tells us to leave the 2 in the hundredth place.

[tex]P \approx 2.02 \ atm[/tex]

The pressure is approximately 2.02 atmospheres and choice D is correct.

step by step of how to convert fahrenheit and celsius to kelvins -5F to kelvins please and thank you

Answers

(-5-32)•5/9 + 273.5= K

(-37)•5/9 + 273.5=K

185/9 + 273.5=K

-20.55+273.5=K

252.59=K


( that 9 is dividing the (-5-32)•5 )

Question 2: thanks!!!

Answers

Ans 33333333333333333333333333 cellulose

Water is dipolar because:
A. It has two hydrogens, each of which pulls oxygen's electrons and separates the
charges into two areas.
B. Oxygen pulls electrons closer to itself than hydrogens, giving the oxygen a
slight negative and hydrogens a slight positive charge.
C. Oxygen pulls electrons closer to itself than hydrogens, giving the oxygen a
slight positive and hydrogens a slight negative charge.
OD. It has two hydrogens, each of which has its own polar area.

Answers

Answer:

B. Oxygen pulls electrons closer to itself than hydrogens, giving the oxygen a slight negative and hydrogens a slight positive charge.

Explanation:

In the water molecule (H2O), an oxygen atom is bonded to two hydrogen atoms. Oxygen atom is much more electronegative (has more attraction for electrons) than hydrogen atom, hence, it pulls electrons from one one of the hydrogen atoms bonded to it making it more negatively charged and the hydrogen atom, more positively charged.

The possession of positive charge (+) and negative charge (-) in the same molecule, caused by uneven flow of electrons is what it means to be DIPOLAR (from dipole). Hence, water is DIPOLAR because oxygen pulls electrons closer to itself than hydrogens, giving the oxygen a slight negative and hydrogens a slight positive charge.

b. What chemist finds
out how much nitrogen is in a sample of air

Answers

rkckfkfkckdkfjcjenrjv

Consider two gases, A and B, which are in a container at room temperature. What effect will the following changes have on the rate of the reaction between these gases?


The temperature is decreased at a constant volume.

A. Increase
B. Decrease

Answers

Answer:

A. The rate of reaction will increase or go up

B. The rate of reaction will decrase or go down.

Explanation:

Increasing the temperature will make the gas particles move faster. Faster movement will increase rate of collision between particles to cause a reaction. Decreasing the temperature will cause the opposite to happen.

What is an alkyne?
A. A hydrocarbon containing all single bonds
B. A hydrocarbon containing a carbon-carbon double bond
C. A hydrocarbon containing a carbon-carbon triple bond
D. A hydrocarbon containing an aromatic ring

Answers

The correct answer is C.

Alkynes are called the hydrocarbons. Ethyne is an important alkyne which is used in oxyacetylene gas cutting. A hydrocarbon containing a carbon-carbon triple bond is the alkyne. The correct option is C.

What is an alkyne?

In organic chemistry, an alkyne is defined as the unsaturated hydrocarbon containing at least one carbon-carbon triple bond. The alkynes are unsaturated hydrocarbons and their general formula is CₙH₂ₙ₋₂ and the triple bond is known as the acetylene bond.

Many alkynes are found in nature. Ethyne is the first member of the alkyne family in which two carbon atoms are connected by a triple bond. Almost all alkynes are also found to be hydrophobic in nature.

Alkynes show three types of isomerism like chain isomerism, position isomerism and functional isomerism. The triple bond present in the alkynes is its functional group.

Thus the correct option is C.

To know more about Alkynes, visit;

https://brainly.com/question/23508203

#SPJ7

2.
In photosynthesis, which substances are used up, which are produced and which are necessary
but remain unchanged after the reaction?
used up
produced
remain
A
carbon dioxide
water
oxygen
A
8
chlorophylt
carbon dioxide
water
с
oxygen
starch
cellulose
D
water
oxygen
chlorophyll

Answers

D. Water is used up, Oxygen is produced and Chlorophyll is necessary, but remains unchanged.

how can you identify if a physical or chemical change has occurred

Answers

Answer:

The difference between a physical reaction and a chemical reaction is what its made of. In a chemical reaction, there is a change in the materials of the substances in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition. Whereas will a chemical change there is not.

Answer:

Answer:

Physical changes are changes affecting the form of a chemical substance, but not its chemical composition. Physical changes are used to separate mixtures into their component compounds, but can not usually be used to separate compounds into chemical elements or simpler compounds.  Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. Some signs of a chemical change are a change in color and the formation of bubbles. The five conditions of chemical change: color chage, formation of a precipitate, formation of a gas, odor change, temperature change. Change in Color. Noticeable Odor (after reaction has begun) Formation of a Precipitate. Formation of Bubbles.  Physical changes are changes that do not alter the identity of a substance. Chemical changes are changes that occur when one substance is turned into another substance. Chemical changes are frequently harder to reverse than physical changes

Explanation:

Please tell me the answer of what is unit? ​

Answers

Answer:

a quantity chosen as a standard in terms of which other quantities may be expressed.

Explanation:

Explanation:

Unit is a standard physical quantity defined and adopted by convention,with other quantity of same kind.

write the electronic configuration of the first 20 element​

Answers

Argon -Potassium-carbon

2 Figure 3.1 shows two different forms of carbon, A and B.
A
B
Figure 3.1
a Name the two forms of carbon shown.

Answers

Answer:

show the pictures pls specify

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