What is the solution to the problem expressed to the correct number of significant figures?
7.21= ?
A. 1.688
OB.
1.69
O C.
1.7:
OD
1.70

Answers

Answer 1

Answer:

(102 900 ÷ 12) + (170 × 1.27) = 8800

Step 1. Evaluate the expressions inside the parentheses (PEMDAS)

102 900 ÷ 12 = 8575

170 × 1.27 = 215.9

In multiplication and division problems, your answer can have no more significant figures than the number with the fewest significant figures.

Thus, the underlined digits are not significant, but we keep them in our calculator to avoid roundoff error.

Step 2. Do the addition (PEMDAS).

  8575

+    215.9

= 8790.9

Everything that you add to an insignificant digit gives an insignificant digit as an answer.

Thus, the underlined digits are not significant.

We must drop them and round up the answer to 8800.

Explanation:


Related Questions

Suppose you add water to 6 g of sugar to make a solution with a concentration of 3 g/l What is the total volume of the solution?

Answers

Answer:

no

Explanation:

9. Good insulator should be
(a) Fire proof
(b) Chemically inert
(c) Odourless in use
(d) All of the above
Ar​

Answers

Answer:

A fire proof

Explanation:

I hope this is help

What does Boyle's Law describe?

Answers

Answer: Image result for What does Boyle's Law describe?

This empirical relation, formulated by the physicist Robert Boyle in 1662, states that the pressure (p) of a given quantity of gas varies inversely with its volume (v) at constant temperature; i.e., in equation form, pv = k, a constant.

Explanation:

How are chemical reactions classified from an energy point of view?​

Answers

Answer:

normanie tykohoukdh    kjdj jj jjd

Explanation:

2. Hydrocarbons consist of carbon and hydrogen. 5.7 g of a hydrocarbon contains 4.8 g of carbon.
If the relative molecular mass of the hydrocarbon is 114, determine its molecular formula.​

Answers

Answer:

The molecular formula of the hydrocarbon compound is C₈H₁₈

Explanation:

The type of chemical substance in the question = Hydrocarbon

The mass of the hydrocarbon = 5.7 g

The mass of carbon in the given hydrocarbon (sample) = 4.8 g

The relative molecular mas of the hydrocarbon = 114 g

Therefore, the mass of hydrogen in the sample, H = 5.7 g - 4.8 g = 0.9 g

The ratio of the mass of carbon in the sample = 4.8/5.7

The ratio of the mass of hydrogen in the sample = 0.9/5.7

By the law of constant composition, we have;

The mass of carbon in a mole of the hydrocarbon = (4.8/5.7) × 114 g = 96 g

The molar mass of carbon, C = 12 g/mol

The number of moles of carbon in a mole of the hydrocarbon, 'n₁', is given as follows;

n₁ = 96 g/12 g = 8 moles

The mass of hydrogen in a mole of the hydrocarbon = (0.9/5.7) × 114 g = 18 g

The molar mass of hydrogen, H ≈ 1 g/mol

The number of moles of hydrogen in a mole of the hydrocarbon, 'n₂', is given as follows;

n₂ = 48 g/1 g = 18 moles

Therefore, in each each molecule of the compound, we have have 8 atoms of carbon, 'C', and 18 atoms of hydrogen, 'H'

Therefore, we get;

The molecular formula of the hydrocarbon compound is C₈H₁₈ which is the chemical formula for the hydrocarbon also known as octane

OMG PLEASEEEE HELPPPPPPPPPPP!!!!!!!!!!!

Answers

Answer:

the second one

Explanation:

THE answers is b

Balance the equation by typing in the correct coefficients into the blank spaces in front of each formula. Type 1 if
the coefficient is 1, do not leave space blank
_EH + _ G2 → _EG + _HG2

Answers

Answer:

2 in front of every one

Explanation:

HOPE IT HELPS

What results when equal but opposite charges are present in two regions of a polar molecule? A. dipole B. ionic bond C. Electron sea D. crystal lattice

Answers

Answer: A. dipole

Explanation:

Dipole can be defined as the separation of the equal and opposite charges present in the molecule via ionic bonding. The water molecule comprising of two molecules of hydrogen being positively charged and one molecule of oxygen being negatively charged are connected via ionic bonding thus water molecule is an example of dipole molecule. There is unequal distribution of the electrical density throughout the molecule.

The polar molecule results in a dipole when equal but opposite charges are present in two regions.

Dipole:  

Dipole arises when a molecule have opposite and equal charge in the ends.

For example - water molecule

In water molecule Oxygen is negatively charged and hydrogen have low electronegativity, this difference in electronegativities arise dipole in molecule.

Therefore, the polar molecule results in a dipole when equal but opposite charges are present in two regions.

To know more about Dipole,

https://brainly.com/question/18382778

HELP PLEASE❗️❗️‼️

An increase in temperature is an increase in.... ( there are two correct answers)
A.) Water molecules
B.) The melting point
C.) pressure
D.) Fun

Answers

C and B

Hope this helps!

If 3.22 g of precipitate are recovered from the reaction of limewater (Ca(OH),) with carbon dioxide to produce
water and calcium carbonate, what is the percent yield if 20.0 g of carbon dioxide was mixed with the
limewater?
the correct answer is 7.1% but i don't understand what they did

Answers

Answer:

Percent yield = 7.1%

Explanation:

The general reaction of the problem is:

Ca(OH)₂ + CO₂ → H₂O + CaCO₃

To solve this question we need to find theoretical yield using the amount of carbon dioxide added because:

Percent yield = Actual yield (3.22g) / Theoretical yield * 100

Theoretical yield is the maximum amount of product that could be obtained. To find it we need to convert the mass of CO₂ to moles. The moles of CO₂ = Moles of CaCO₃:

Moles CO₂ -Molar mass: 44.01g/mol):

20.0g * (1mol / 44.01g) = 0.454 moles CO₂ = Moles of CaCO₃ produced

Mass CaCO₃ = Theoretical yield -Molar mass: 100.09g/mol-:

0.454 moles * (100.09g / mol) = 45.5g of CaCO₃ = Theoretical yield.

Replacing:

Percent yield = 3.22g / 45.5g * 100

Percent yield = 7.1%

The three types of intermolecular forces have different strengths. Rank
them from weakest to strongest.

Answers

There are three different types of intermolecular forces in terms of strength. They are (strongest to weakest) hydrogen bonding, dipole-dipole and Van der Waals' forces.

Calculate the number of moles of NaOH contained in 250. mL of a 0.05M solution.

Answers

Answer:

0.0125mol

Explanation:

Molarity (M) = number of moles (n) ÷ volume (V)

n = Molarity × Volume

According to this question, a 0.05M solution contains 250 mL of NaOH. The volume in litres is as follows:

1000mL = 1L

250mL = 250/1000

= 0.250L

n = 0.05 × 0.250

n = 0.0125

The number of moles of NaOH is 0.0125mol.

How do you find the scientific notation of a Avogadro's number??

Answers

Answer: ummmmmm hmmmmm

Explanation:

How many lone pairs does this molecule have?

Answers

Answer:

Just 1 i.e., Option B.

Because except for top of the molecule, all other sides are filled with a letter meaning there is one free space.

Answer:

B

Explanation:

H .  +  H .   ----->  H:H            {":" represents a covalent bond, that is, a shared pair of electrons}

A Lewis structure is a convention used to represent the covalent bonding in a molecule.   Dots or lines are used to represent

valence electrons (electrons available for bonding).  The Lewis structure for the hydrogen molecule is as follows.

     H:H  or  H-H

A bonding pair is an electron pair shared between two atoms.

A nonbonding pair (lone pair, unshared pair) is a pair of electrons that remains on one atom and is not shared.

4 Hydrogen has three naturally occurring isotopes. H.1, H-2, and H-3 The atomie mass of Hydrogen is 1.097 Which isotope is most abundant in nature? Explain​

Answers

Answer:

The number following the name of the element is the number of subatomic particles inside the nucleus of the atom. This means that it is the mass number of the isotope. The average atomic mass of the element is the sum of the products of the percentage abundance and mass number of the naturally occurring isotopes.

Since, the average atomic mass of the hydrogen is nearest to 1 then, the most abundant isotope should be hydrogen-1.

It late, I need help quick

Answers

Answer:

what is late ? there is no attachment ?

Answer:

For people asking for the questions

Explanation:

Write the equilibrium expressions for each of the following equilibria:
a. 2 Ba + O2 ⇌ 2 BaO
b. 2 Mg + O2 ⇌ 2MgO
c. P4 + 5 O2 ⇌ P4O10

Answers

Answer:

a.

[tex]K=\frac{[BaO]^2}{[Ba]^2[O_2]}[/tex]

b.

[tex]K=\frac{[MgO]^2}{[Mg]^2[O_2]}[/tex]

c.

[tex]K=\frac{[P_4O_{10}]^2}{[P_4][O_2]^5}[/tex]

Explanation:

Hello!

In this case, since the equilibrium expression is set up by dividing the products over the reactants and powering to the stoichiometric coefficient, we can proceed as follows:

a. 2 Ba + O2 ⇌ 2 BaO.

[tex]K=\frac{[BaO]^2}{[Ba]^2[O_2]}[/tex]

b. 2 Mg + O2 ⇌ 2MgO

[tex]K=\frac{[MgO]^2}{[Mg]^2[O_2]}[/tex]

c. P4 + 5 O2 ⇌ P4O10

[tex]K=\frac{[P_4O_{10}]^2}{[P_4][O_2]^5}[/tex]

Best regards.

Which of the following chemical reactions produces water via a
synthesis reaction?
a 2H2 + O2 + 2H2O
b NaOH + HCI - NaCl + H2O
C CuO + H2 - Cu + H2O
d H2CO3 → CO2 + H2O

Answers

Answer:

Should be A, but also I think there should be an arrow between O2 and 2H2O

How many grams are in 8.50 e 23 formula units of NaCl?
a)82.5 g
b)8.25 g
c)85.0 g
d)91.5 g

Answers

Answer:

a)82.5 g

Explanation:

To solve this problem we will use Avogadro's number, which states the number of formula units per mole.

8.50x10²³formula units ÷ 6.023x10²³ formula units/mol = 1.41 mol

Then we convert 1.41 moles of NaCl to grams, using its molar mass:

1.41 mol NaCl * 58.44 g/mol = 82.4 g

The closest answer is option a).

The molar mass of two equally sized samples of unknown gaseous compounds is shown in the table. Molar Mass Comparison Gas Molar Mass A 17 g/mol B 36.5 g/mol Which statement describes the density and diffusion of both gases at STP? Gas A has a higher density and diffuses faster than Gas B. Gas A has a higher density and diffuses slower than Gas B. Gas A has a lower density and diffuses faster than Gas B Gas A has a lower density and diffuses slower than Gas B.

Answers

Answer:

Effusion  is the process of a gas being poured out through a hole diametrically smaller than the structural exit of the container.

A lighter gas effuses faster than a heavier gas.

Thus gas A has a lower density and effuses slower than Gas B.

Explanation:

The gas with a lower molar mass will have a lower density and diffuses at a slower rate. Thus gas A has a lower density than gas B and diffuses slower than gas B.

Three points should be noted here;

The density of any substance is related to the molar mass.[tex]D=M/V[/tex], where [tex]D[/tex] is the density, [tex]M[/tex] is the mass and [tex]V[/tex] is the volume of the substance.The density of the gas is directly proportional to the molar mass of the gas.

Hence the gas A has lower density and the gas B has higher density as the molar mass of A is [tex]17 g/mol[/tex] and of B is [tex]36.5 g/mol[/tex].

About Diffusion please note the below points;

Diffusion is the process of movement of a substance from the area of higher concentration to the area of lower concentration.The gas with a smaller mass will diffuse slower in rate than the gas with a higher mass.

Hence the gas A diffuses slower in rate than gas B.

Thus the correct answer is "Gas A has a lower density and diffuses slower than Gas B".

Learn more about the density of gas here: https://brainly.in/questions/16376906

is lime flavor ionic or covalent​

Answers

Answer:Calcium carbonate (CaCO3), essentially, is an ionic compound having the bivalent calcium and carbonate ions. But the carbonate anion is a polyatomic species. The carbon atom is bonded to all the three oxygen atoms by covalent bonds - two carbon-oxygen single bonds and one carbon-oxygen double bond.

Explanation:So it's ionic hope this helps u. Btw may i have brainlist plz.

How did chemists make their proposed model of the sub atomic particles?

Answers

Answer:

Because they want to clarify or give solution to the particle that the other didn't know

Explanation:

Correct me if im wrong thanks

What is the correct formula for sodium carbonate?
a. Na(CO3)2
b. Na,(CO3)2
C. Na2CO3
Naz(CO)2
e. NaCO3
d.
a
a
b
b
ΟΟΟΟΟ
С
С
d
d
е
e

Answers

Answer:

na2 co3

Explanation:

sodium carbonate formula

Answer:

your answer is C.

Explanation:

this is what it would be like

O

|

|

Na+ C Na+

/ \

/ \

O- O-

Please help me, I am confused

Answers

Answer:

B

Explanation:

Ionic compound can conduct electricity

A rectangular poster is /4 yard wide and / yard tall. What is its area? Solve this problem any way you choose

Answers

Answer:

Area of rectangular poster = [tex]\frac{3}{16}[/tex] yard²

Explanation:

P.S - The exact question is -

Given - A rectangular poster is [tex]\frac{1}{4}[/tex] yard wide and [tex]\frac{3}{4}[/tex] yard tall.

To find - What is its area ?

Proof -

We know that ,

The area of rectangle = Length × Breadth

Here,

Given that,

Length of rectangle = [tex]\frac{3}{4}[/tex] yard

Breadth of rectangle = [tex]\frac{1}{4}[/tex] yard

∴ we get

Area of rectangular poster = [tex]\frac{3}{4}[/tex] × [tex]\frac{1}{4}[/tex]  yard²

                                          = [tex]\frac{3}{16}[/tex] yard²

⇒Area of rectangular poster = [tex]\frac{3}{16}[/tex] yard²

if carbon dioxide is broken down. what element will it give?​

Answers

Carbon dioxide is CO2...if it’s broken down it will be C and O which are carbon and oxygen

HELP ME PLEASEEEEE!!!!!!!!!!

Answers

Answer:

I dont know what the answer is

Explanation:

The answer is c because a acid when an acid is dissolved in water, the balance between hydrogen ions and hydroxide ions is shifted. Now there are more hydrogen ions than hydroxide ions in the solution. This kind of solution is acidic.

If today is Monday and it is a 1st Quarter moon, what phase will it
be on Thursday?

Answers

Answer:

Wanning gibouss 56%

Explanation:

Waning gibbous ... I’m sadly doing this too it’s difficult but it gets easy

Measurements show that unknown compound X has the following composition:
element mass %
carbon 74.8%
hydrogen 25.1%
Write the empirical chemical formula of X. please help

Answers

X is carbon and Jess

the empirical chemical formula of X is CH4

Explanation:Step 1: Imagine you have a sample of compound weighing exactly . Multiply the mass of this sample by the mass percents to find the mass of each element in the sample

Step 2: Divide the mass of each element by the element's molar mass to find the moles of each element in the sample. Remember to round your answers to the correct number of significant digits.  

Step 3: Divide the moles of each element by the the smallest number of moles of any element to find the mole ratio of elements in the sample.  

Step 4: Multiply the mole ratio by the smallest whole number that changes it into a whole number ratio to find the atom ratio of elements in the sample.

Note that the result of each multiplication must equal a whole number only within measurement uncertainty.  

The measurement uncertainty in this calculation comes from the measurement uncertainty of the mass percents given in the question. The mass percents each have significant digits. That means each mass percent has some measurement uncertainty in the third significant digit, and only the first two significant digits can be considered completely reliable.  

In Step 1 you multiplied each mass percent by something with zero uncertainty (the exactly you assumed your sample weighed), in Step 2 you divided by a measurement with more than significant digits (the molar mass of the elements), and in Step 3 you divided by a measurement with the same number of significant digits (the least number of moles of any element in the compound). None of these steps added to the measurement uncertainty of your calculation.  

Therefore, the measurement uncertainty in the final result of all your calculations is determined by the measurement uncertainty in the original mass percents and will be in the third significant digit. That means the result of each of the final multiplication steps must equal a whole number only to within the first two significant digits.  

The whole numbers in the last column of the table are and .  

Unicellular organisms are so small that you usually need a telescope to see them.

True
False

Answers

Answer:

true ........

hope it is helpful

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