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3 years ago

How many significant figures are in the measurement 40,500 mg?

Chemistry

1 answer:

schepotkina [342]3 years ago

3 0

b) three

this is because all integers are sig figs, and all numbers between integers are sig figs. This makes the 40,5 part of 40,500 significant. Place holder zeroes that are not after a decimal are not significant, so the last two zeroes of the number are not significant.

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Substance A has the following properties.

ella [17]

It will take 1.11 min to heat the sample to its melting point.

Melting point = - 20°C

Boiling point = 85°C

∆H of fusion = 180 J/g

∆H of vap = 500 J/g

C(solid) = 1.0 J/g °C

C(liquid) = 2.5 J/g °C

C(gas) = 0.5 J/g °C

Mass of sample = 25 g

Initial temperature = - 40°C

Final temperature = 100°C

Rate of heating = 450 J/min

Specific heat capacity formula:- q = m ×C×∆T

Here, q = heat energy

m = mass

C = specific heat

∆T = temperature change

Melting point = - 20°C

C(solid) = 1.0 J/g °C

∆T = final temperature - initial temperature = -20 - (-40) = 20

Put these value in Specific heat capacity formula

q = m ×C×∆T

q = 25×1.0×20

=500J

The Rate of heating = 450 J/min

i.e. 450J = 1min

so, 500J = 1.11min

1.11 minutes does it take to heat the sample to its melting point.

The specific heat capacity is defined as the amount of heat absorbed in line with unit mass of the material whilst its temperature increases 1 °C.

Learn more about specific heat capacity here:- brainly.com/question/26866234

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3 0

1 year ago

What is the gram formula of na2co3

makkiz [27]

Answer:

106 gfm

Explanation:

element. number masses

Na. 2 23×2

C. 1. 12

O. 3. 16×3

then add

106 gfm

5 0

2 years ago

Consider the molecules: scl2, f2, cs2, cf4, and brcl. select the choice where the bonds of the molecules are arranged in order o

elena-s [515]

The polarity of a bond depends on the difference in electronegativities of the atoms involved in bonding. Greater this difference, greater is the polarity

1) In SCl2 we have the S-Cl bond

Electronegativity values: S = 2.5, Cl = 3

Difference = 3.0 -2.5 = 0.5

2) In F2 we have the F-F bond

Electronegativity value: F = 4.0

Difference = 4.0-4.0 = 0

3) In CS2 we have the C-S bond

Electronegativity value: C = 2.5, S = 2.5

Difference = 2.5 -2.5 = 0

4) In CF4 we have the C-F bond

Electronegativity values: C = 2.5, F = 4.0

Difference = 4.0 -2.5 = 1.5

5) In BrCl we have the Br-Cl bond

Electronegativity values: Br = 2.8, Cl = 3

Difference = 3.0 -2.8 = 0.2

Therefore, the increasing order of polarity is

F2 = CS2 < BrCl < SCl2 < CF4

5 0

2 years ago

Write the ground state electron configuration of zn using the noble-gas shorthand notation.

V125BC [204]

Atomic Number of Zinc is 30, means it contains 30 electrons. So, its electronic configuration is as follow,

1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰
As,
1s², 2s², 2p⁶, 3s², 3p⁶ = Argon
So,
Electronic configuration of Zinc in shorthand notation is as follow,

[Ar] 4s², 3d¹⁰

8 0

2 years ago

How many grams of NaOH are produced from 1.20 x 10^2 of Na2O

oksian1 [2.3K]

Write an balance the equation

Na2O + H2O -> 2 NaOH

Calculate the molecular mass of Na2O and NaOH from the atomic mass from the periodic table.

Na = 23
O=16
H=1

Na2O = 23 * 2 + 16 = 62
NaOH = 23+16+1= 40

For the stoichiometry of the reaction one mole of Na2O = 62g produce two mol of NaOH = 2* 40= 80 g

120 g Na2O x 80g NaOH / 62g Na2O=

154.8 g NaOH

5 0

3 years ago