Round off the following numbers to the number of significant figures (sf) indicated.
a. 7.524 to 3 sf ______
b. 16.465 to 3 sf ______
c. 84.996 to 2 sf ______
d. 6.02502 to 2 sf ______​

Answer:

Explanation:

1.

[tex]1000 \:g = \:1\:kilogram\\x \: grams = 38,000\:kilogram\\\\x = 38,000,000 \:grams[/tex]

2.

[tex]1 \:ml =0.001\:l\\4.3\:ml =x\: l\\\\x = 0.0043[/tex]

3.

[tex]1\:m= 1000\:mm\\6.5\:m = x\\\\x = 6500 mm[/tex]

4.

[tex]1\:km = 100,000\:cm \\0.02km = x\:cm\\\\x = 2000\:cm[/tex]

5 .[tex]20\°C = 20+273 \\= 293 K[/tex]

Answer:

Ionic, metal, organic

Explanation:

In this case, we have to analyze each compound:

-) [tex]CaCl_2 [/tex]

In this compound, we have a non-metal atom (Cl) and a metal atom (Ca) . So, we will have a high electronegativity difference between these atoms, With this in mind, we will have an ionic bond. Ions can be produced:

[tex]CaCl_2~->~Ca^+^2~+~2Cl^-[/tex]

The cation would be [tex]Ca^+^2[/tex] and the anion is [tex]Cl^-[/tex]. So, we will have an ionic compound.

-) [tex]Cu[/tex]

In this case, we have a single atom. If we check the periodic table we will find this atom in the transition metals section (in the middle of the periodic table). So, this indicates that Cu (Copper) is a metal.

-) [tex]C_2H_6[/tex]

In this molecule, we have single bonds between carbon and hydrogen. The electronegativity difference between C and H are not high enough to produce ions. So, with this in mind, we will have covalent bonds. This is the main characteristic of organic compounds. (See figure 1)

CaCl₂, Cu, C₂H₆ are ionic, metal, and organic compounds, respectively.

CaCl₂ is formed by a metal (Ca) and a non-metal (Cl). Due to the difference in their electronegativities, they form ionic compounds. These compounds tend to have high melting and boiling points and conduct electricity in aqueous solution.

Cu is a transition metal. It is a good electric and heat conductor, which is why it is used in cables. It also has high melting and boiling points.

C₂H₆ (ethane) is a hydrocarbon, that is, an organic compound (formed by at least C and H). They are bad conductors and have low melting and boiling points.

CaCl₂, Cu, C₂H₆ are ionic, metal, and organic compounds, respectively.

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Answer:

20 mL

2 cL

Explanation:

We can use the base 10 decimal system to get equivalent measurements:

1 L = 1000 mL

1 L = 100 cL

Answer:

[tex]m_{O_2}=6gO_2[/tex]

Explanation:

Hello,

In this case, given the reaction:

[tex]2S+3O_2\rightarrow 2SO_3[/tex]

Thus, for 4.00 g of sulfur (atomic mass = 32 g/mol), we apply the shown 2:3 mole ratio with oxygen (molar mass = 32 g/mol) in order to compute its requirement:

[tex]m_{O_2}=4.00gS*\frac{1molS}{32gS}*\frac{3molO_2}{2molS}*\frac{32gO_2}{1molO_2}\\ \\m_{O_2}=6gO_2[/tex]

Best regards.

The mass of oxygen would be required is [tex]6gO_2[/tex]

[tex]= 4.00 \times \frac{1molS}{32gS} \times \frac{3molO_2}{2molS} \times \frac{32gO_2}{1molO_2} \\\\= 6gO_2[/tex]

Here for 4.00 g of sulfur (atomic mass = 32 g/mol), we used the shown 2:3 mole ratio with oxygen (molar mass = 32 g/mol).

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Answer:

If 33.6 g of NO and 26.9 g of O₂ react together, 51.52 grams of NO₂ can be formed.

Explanation:

You know: 2 NO (g) + O₂ (g) → 2 NO₂ (g)

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of reagent and product participate in the reaction:

Being:

the molar mass of the compounds participating in the reaction is:

Then, by stoichiometry of the reaction, the following amounts of reactant and product participate in the reaction:

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

You can apply the following rule of three to determine the limiting reagent: if by stoichiometry 60 g of NO react with 32 g of O₂, 33.6 g of NO with how much mass of O₂ will it react?

[tex]mass of O_{2}=\frac{33.6 grams of NO*32 grams of O_{2} }{60 grams of NO}[/tex]

mass of O₂= 17.92 grams

But 17.92 grams of O₂ are not available, there are 26.9 grams available. Since it has more mass than it needs to react with 33.6 grams of NO, NO will be the limiting reagent.

Then you apply the following rule of three: if by reaction stoichiometry 60 grams of NO form 92 grams of NO₂, 33.6 grams of NO how much mass of NO₂ does it form?

[tex]mass of NO_{2}=\frac{33.6 grams of NO*92 grams of NO_{2} }{60 grams of NO}[/tex]

mass of NO₂= 51.52 grams

If 33.6 g of NO and 26.9 g of O₂ react together, 51.52 grams of NO₂ can be formed.

Answer:

D d

Explanation:

Answer:

150.7

Explanation:

162.5 - 11.8 = 150.7

Given :

Some volume measurements :

[tex]0.75 \times 10^{-3}\ mL,\ 325\ \mu L,\ 4.11 \times 10^{-4}\ dL[/tex]

To Find :

Rank the measurements from largest to smallest.

Solution :

Now , [tex]1\ \mu l=10^{-3}\ ml[/tex].

Also , [tex]1\ dl=100\ ml[/tex].

So , the measurements in same units are :

[tex]0.75 \times 10^{-3}\ mL,\ 325 \times 10^{-3}\ mL , 4.11 \times 10^{-4} \times 100\ mL\\\\0.75\times 10^{-3}\ mL ,\ 325\times 10^{-3}\ mL ,\ 41.1\times 10^{-3}\ mL[/tex]

So , the order from highest to lowest is :

[tex]325\times 10^{-3}\ mL ,\ 41.1\times 10^{-3}\ mL ,\ 0.75\times 10^{-3}\ mL[/tex]

Hence , this is the required solution .

325 µL > 41.1 µL > 0.75 µL is the ranking of the measurements from largest to smallest.

Measurements have a crucial role in many aspects of daily life, including science, engineering, construction, and cookery. They enable precise measurement, comparison, and communication of an object's size, quantity, or amount. The most widely used measurement systems globally are the metric and imperial systems. There are other measurement systems as well. The International System of Units (SI), generally known as the metric system and based on multiples of ten, is extensively used. It comprises measures for length and mass including metres, grammes, and litres. Units like feet, pounds, and gallons are part of the imperial system, which is primarily used in the United States.

1 mL = 1000 µL      

1 dL = 100 mL

.75 x [tex]10^{-3}[/tex] mL = .75 x [tex]10^{-3}[/tex] x 1000 µL

                      = 0.75 µL

4.11 x [tex]10^{-4}[/tex] dL = 4.11 x[tex]10^{-4 }[/tex]x 100 mL

                     = 0.0411 mL

                     = 41.1 µL

325 µL > 41.1 µL > 0.75 µL

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Answer:

5.265L/body ; 68.9×10³ kg / beat

Explanation:

Given the following :

Resting pulse rate = 81 beats / minute

Amount of blood pumped per beat = 65mL = (65 / 1000)L = 0.65L

Density of blood = 1060 kg/m^3

Circulation time = 1 minute for a person at rest

A.) How much blood is in the body?

Resting pulse rate × amount of blood pumped per beat * circulating time

(81 beat / min) × 0.65L/beat * 1minute / body = 5.265L / body

B.) b. On average, what mass of blood does the heart pump with each heart beat?

0.065L/beat * 1m³/1000L= 0.000065 m³ / beat

From density = mass / volume ;

Average mass = density * volume

= 1060kg/m³ * 0.000065 m³ / beat

= 0.0689kg / beat

= 68.9 × 10³ kg / beat

Answer:

You should rinse your head thoroughly ASAP, don't try to blow on the chemical or anything. Its going burn, you have to let your head cool off.

Explanation:

why rinse off your hand? you're getting the fluid away fast, so I can't infect your skin that much.

Answer:

THE MOLARITY IS 2.22 MOL/DM3

Explanation:

The solution formed was as a result of dissolving 37.5 g of Na2S in 217 g of water

Relative molecular mass of Na2S = ( 23* 2 + 32) = 78 g/mol

Molarity in g/dm3 is the amount of the substance dissolved in 1000 g or 1 L of the solvent. So we have;

37.5 g of Na2S = 217 g of water

( 37.5 * 1000 / 217 ) g = 1000 g of water

So, 172.81 g/dm3 of the solution

So therefore, molarity in mol/dm3 = mol in g/dm3 / molar mass

Molarity = 172.81 g/dm3 / 78 g/mol

Molarity = 2.22 mol/dm3

The molarity of the solution is 2.22 mol/dm3

Answer:

The answer is 2.22mol

Explanation:

Answer: D

Explanation:

i just took the ck-12 quiz and that was the right answer

Answer:

5.physical change

6.chemical change

7.physical change

8.conservation of mass

9.thermal energy

10.physical change

I honeslty dont know if this is right

explanation:

Answer:

Force, [tex]F=7.3\times 10^{36}\ N[/tex]

Explanation:

We need to find the force of the Earth on the moon be when the moon is 2.0D from the Earth.

The force that act between Earth and the Moon is gravitational force. It is given by :

[tex]F=\dfrac{Gm_1m_2}{r^2}[/tex]

We have,

[tex]m_1=\text{mass of Earth}=5.972 \times 10^{24}\ kg[/tex]

[tex]m_2=\text{mass of Moon}=7.34\times 10^{22}\ kg[/tex]

So,

[tex]F=\dfrac{6.67\times 10^{-11}\times 5.972 \times 10^{24}\times 7.34\times 10^{22}}{(2)^2}\\\\F=7.3\times 10^{36}\ N[/tex]

So, the force of the Earth on the Moon is [tex]7.3\times 10^{36}\ N[/tex].

Answer:

1. more slowly than

2. larger than

3. weaker

Explanation:

Acetone molecules are bonded by very weak intermolecular forces when compared to that of the hydrogen bond between water molecules. This makes it very easy for acetone molecules to vaporize easily into its gaseous state, much more faster than water molecules (since the acetone molecules need a lesser amount of energy to break these bonds). Also, the boiling point of liquid acetone is much lower than that of water, meaning that it has a higher vapor pressure than that of water.

Answer:

65.8 and it is shown considering the significant figures of the shortest number.

Explanation:

Hello,

In this case, when we add 25.4 and 40.433 the result is 65.833, nevertheless, the result is shown based on the initial number having the fewest amount of significant figures that in this case is 25.4 that has three, therefore, the result must be 65.8 and it is shown considering the significant figures of the shortest.

Regards.

Answer:

The pH of the solution is 4.69

Explanation:

Given that,

Mass of potassium = 2.643 grams

Weight of water = 50.00 mL

Weight of HCl=100.00 ml

Mole = 0.120 M

We know that,

[tex]KCH_{3}(CH_{2})_{2}CO_{2}[/tex] is a basic salt.

Let's write it as KY.

The acid [tex]HCH_{3}(CH_{2}CO_{2})[/tex] would become HY.

We need to calculate the moles of KY

Using formula of moles

[tex]moles\ of\ KY=\dfrac{m}{M}\times1000[/tex]

[tex]moles\ of\ KY=\dfrac{2.643}{126}\times1000[/tex]

[tex]moles\ of\ KY=20.97\ m\ mole[/tex]

The reaction is

[tex]KY+HCl\Rightarrow HY+ KCl[/tex]

The number of moles of KY is 20.98 m

initial moles = 20.98

Final moles [tex]m=20.98-0.120\times100= 8.98[/tex]

We need to calculate the value of pKa(HY)

Using formula for pKa(HY)

[tex]pKa_{HY}=-log Ka[/tex]

[tex]pKa_{HY}=-log(1.5\times10^{-5})[/tex]

[tex]pKa_{HY}=4.82[/tex]

We need to calculate the pH of the solution

Using formula of pH

[tex]pH=pKa+log(\dfrac{[KY]}{[KH]})[/tex]

Put the value into the formula

[tex]pH=4.82+log(\dfrac{8.98}{12})[/tex]

[tex]pH=4,69[/tex]

Hence, The pH of the solution is 4.69

Answer:

CH3OH > CH3Cl > CH4

Explanation:

The boiling point of a compound depends on the nature and magnitude of intermolecular forces acting between its molecules.

Methanol contains the -OH group, hence hydrogen bonds are dominant intermolecular forces in the compound. Presence of hydrogen bonds increases the boiling point of a substance, hence methanol has the highest boiling point followed by chloromethane which has dipole-dipole interaction as dominant intermolecular forces and methane having only weak dispersion forces as dominant intermolecular forces.

Answer:

Following are the explanation of the Rube Goldberg device:

Explanation:

According to the Rube Goldberg devices, which conform with "the energy conservation law," choose a chain of events to carry out such a basic task differently, for this unit, a range of instant theatrical resources are converted into possible energy. It is also responsive to an energy conservation law.

Answer:

0.5g/cm^3

Explanation:

Density = Mass / Volume

Density = 20g / 42cm^3

Density = 0.476g/cm^3

note*: round to the nearest sigfig

Answer is: 0.5g/cm^3

The box's volume is 42cm³ and the mass is 20g then the density is 0.5g/cm³.

The mass of a substance per unit of volume is its density. Density is most frequently represented by the symbol, however the Latin letter D may also be used. Density is calculated mathematically by dividing mass by volume.

How much "stuff" is contained in a specific quantity of space is determined by its density. For instance, a block of the harder, lighter element gold (Au) will be denser than a block of the heavier element lead (Pb) (Au).

Because it enables us to predict which compounds will float and which will sink in a liquid, density is a crucial notion. As long as an object's density is lower than the liquid's density, it will often float.

Density = Mass ÷ Volume

Density = 20g ÷ 42cm³

Density = 0.476g/cm³

= 0.5g/cm³

Thus, the density is  0.5g/cm³.

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Answer:

123.0*12.35/(0.05*6.049)

first do in small bracket 123.0*12.35/0.30245

and then divide 123.0*40.83319557

and multiply 5022.483055

Answer:

aluminium is all of isotope with 14 neutrons .

Answer:

there are 4.0205 Litres of plasma in 8.5 pints

Explanation:

Recall that:

1 quart qt = 2 pints pt  and 1 quart = 946 mL

∴ two pints will contain 946 mL

and one pint will be = 946 mL/2

=  473 mL

Similarly, 8.5 pints will contain 473 mL × 8.5 = 4020.5  mL

We know that :

1000 mL = 1 Litres

Hence 4020.5 mL = (4020.5 /1000)L

= 4.0205 Litres

Therefore, there are 4.0205 Litres of plasma in 8.5 pints

There are 4.0205 Litres of plasma in 8.5 pints

1 quart qt = 2 pints pt  

and

1 quart = 946 mL

So, two pints will contain 946 mL

and one pint will be = [tex]946 mL\div 2[/tex]=  473 mL

Now

8.5 pints will contain

[tex]= 473 mL \times 8.5[/tex]

= 4020.5  mL

We know that :

1000 mL = 1 Litres

Hence 4020.5 mL = (4020.5 /1000)L

= 4.0205 Litres

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Answer:

lithium phosphate

Explanation:

The name of the given ionic compound is lithium phosphate. The correct option is D.

Ionic compounds are neutral compounds composed of positively charged cations as well as negatively charged anions.

For binary ionic compounds, the identity of the cation is written first, accompanied by the title of the anion.

Ionic compounds are made up of ions that are held together through the force of attraction between oppositely charged ions.

One of the most well-known ionic compounds is common salt. Molecular compounds are made up of discrete molecules that are held together by sharing electrons, a process known as covalent bonding.

Lithium phosphate (Li3PO4) is an ionic compound that is primarily used as a conductive thin-film electrolyte in the fabrication of high performance energy storage devices.

Thus, the correct option is D.

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Answer:

The trade was difficult with the old system.

Explanation:

The existing system for the measurement of goods did not work well in the trade because there are different system used by the people of different cities so metric system was used in the whole country in place of the old system of measurement during the French Revolution in order to make the trade easier and quick across the country. This metric system is extensively used in the trade as compared to the old system of measurement due to its easiness and fast.

Answer:

[tex]Ka=5x10^{-4}[/tex]

[tex]pH=1.92[/tex]

Explanation:

Hello,

In this case, given the percent ionization and the concentration of the acid, one computes the concentration of hydrogen ions as follows:

[tex]\% ionization=\frac{[H^+]}{[HA]}*100\%[/tex]

[tex][H^+]=\frac{\% ionization*[HA]}{100\%} =\frac{4\%*0.30M}{100\%}=0.012M[/tex]

Therefore the Ka is computed by using the equilibrium expression:

[tex]Ka=\frac{[H^+][A^-]}{[HA]} =\frac{0.012M*0.012M}{0.30M-0.012M}\\ \\Ka=5x10^{-4}[/tex]

And the pH:

[tex]pH=-log([H^+])=-log(0.012)\\\\pH=1.92[/tex]

Regards.

Answer:

CH₃(CH₂)₁₀COONa

Explanation:

The compounds given are

NaCl

CH₃COOH

CH₃COONH₄

CH₃(CH₂)₁₀COONa

CH₃(CH₂)₁₀CH₃

CH₃(CH₂)₁₀COONa will form micelle . Micelle are formed by soap solution which helps in the removal of oily dirt from our clothes . They are spherical shaped tiny droplet of oil which contains the tail of long chain organic compound like salt of long chain fatty  acids . The surface of the droplet is lined with the tip of the chain which consists of negative charge of the tail end . On the average , each micelle contains a specific amount of charge . Due to it , they make colloidal solution in the water and gets washed off my water . The oily dirt is thus removed .

CH₃(CH₂)₁₀COONa   ⇄     CH₃(CH₂)₁₀COO⁻   +    Na⁺

CH₃(CH₂)₁₀COO⁻  part which is long chain of fatty acid gets adsorbed by oily droplet formed by oily dirt  and forming micelle .

Answer:

An acid with Kg = 1.3 times 10-10.

Explanation:

The formula for pH of a buffer solution is as follows

pH = pKa + log [ A⁻ ] / [ HA ]

HA is acid concentration and A⁻ is concentration of conjugate base .

Generally the the second term is very small so neglecting this figure

pH = pKa

9.8 = pKa

If Ka = 10⁻¹⁰ x 1.3

pKa = - log ( 10⁻¹⁰ x 1.3 )

= 10 - log 1.3

= 9.8 approx .

Hence option F is correct .