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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.

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

Explanation:

Answer:

99

Explanation:

it is matter so it and it has.bein 99

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.

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

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.

Answer:

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

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Answer:

C

Explanation:

Answer:

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

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

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.

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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:

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

Explanation:

Answer:

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

oxidizing agent = KMnO₄

reducing agent = KBr

Explanation:

KMnO₄ -> 2Mn⁷⁺ + 10e⁻ = 2Mn²⁺

KBr -> 10Br⁻⁺ - 10e⁻ = 10Br⁰

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.

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.

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Answer:

show the pictures pls specify

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]

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]

Answer:

homogeneous mixture must be the answer

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.

Answer:

convection is my correct answer

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.

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:

Answer:

D - g/mol

step by step method

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

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