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2 years ago

73.4 km to m then answer in correct number of significant numbers

Chemistry

1 answer:

Fittoniya [83]2 years ago

8 0

Answer:

<em><u>To determine the number of significant figures in a number use the following 3 rules:</u></em>

<em><u>To determine the number of significant figures in a number use the following 3 rules:Non-zero digits are always significant.</u></em>

<em><u>To determine the number of significant figures in a number use the following 3 rules:Non-zero digits are always significant.Any zeros between two significant digits are significant.</u></em>

<em><u>To determine the number of significant figures in a number use the following 3 rules:Non-zero digits are always significant.Any zeros between two significant digits are significant.A final zero or trailing zeros in the decimal portion ONLY are significant.</u></em>

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How many moles of ethane gas, C2H6(g), will occupy 15.0 L at 30 degrees Celsius and 5.0 atm?

Alenkinab [10]

Answer:

3 mol

Explanation:

Given data:

Volume of ethane = 15.0 L

Temperature = 30°C

Pressure = 5.0 atm

Number of moles of ethane = ?

Solution:

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K

T = temperature in kelvin

Now we will convert the temperature.

30+273 = 303 K

5.0 atm × 15.0 L = n×0.0821 atm.L/ mol.K × 303 K

75 atm.L = n× 24.87 atm.L/ mol

n = 75 atm.L / 24.87 atm.L/ mol

n = 3 mol

8 0

3 years ago

Which physical property can be measured??

Nikitich [7]

Extensive property (like volume and mass), can be measured.

4 0

3 years ago

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How many moles is 17.6 g NaOH?

Lynna [10]

Answer:

$\boxed {\boxed {\sf D. 0.440 \ mol \ NaOH}}$

Explanation:

To convert from moles to grams, the molar mass is used (mass of 1 mole). The values are the same as the atomic masses on the Periodic Table, but the units are grams per mole (g/mol) instead of atomic mass units.

<h3>1. Molar Mass</h3>

We are given the compound sodium hydroxide (NaOH) and we need to look up the molar masses of the individual elements.

Na: 22.9897693 g/mol
O: 15.999 g/mol
H: 1.008 g/mol

The formula for the compound has no subscripts, so there is 1 mole of each element in 1 mole of the substance. We can simply add the molar masses.

NaOH: 22.9897693 + 15.999 + 1.008 = 39.9967693 g/mol

This means there are 39.9967693 grams of sodium hydroxide in 1 mole.

<h3>2. Convert Grams to Moles </h3>

Use the molar mass we found as a ratio.

$\frac {39.9967693 \ g \ NaOH}{ 1 \ mol \ NaOH}$

Since we are converting 17.6 grams of NaOH to moles, we multiply by this value.

$17.6 \ g\ NaOH *\frac {39.9967693 \ g \ NaOH}{ 1 \ mol \ NaOH}$

Flip the ratio so the units of grams of NaOH cancel.

$17.6 \ g\ NaOH *\frac {1 \ mol \ NaOH}{ 39.9967693 \ g \ NaOH}$

$17.6 *\frac {1 \ mol \ NaOH}{ 39.9967693}$

$\frac{17.6 }{ 39.9967693} \ mol \ NaOH$

$0.4400355406 \ mol \ NaOH$

<h3>3. Round </h3>

The original measurement of grams has 3 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place.

0.4400355406

The 0 in the ten thousandths place (in bold above) tells us to leave the 0 in the thousandth place.

$0.440 \ mol \ NaOH$

17.6 grams of sodium hydroxide are equal to <u>0.440 moles of sodium hydroxide.</u>

3 0

3 years ago

Write the chemical equation for this reaction. Use the picture I provide!

Lesechka [4]

Answer:

H2O

Explanation:

because the are only two hydrogen that can react to Oxygen

3 0

2 years ago

18. The mass of a quantity of NiCl2 is 24.6 g. How many formula units are in the sample?

Charra [1.4K]

Answer is: A. 1.1 3 1023 NiCl2 formula units.

m(NiCl₂) = 24.6 g; mass of nickel(II) chloride.

M(NiCl₂) = 129.6 g/mol; molar mass of nickel(II) chloride.

n(NiCl₂) = m(NiCl₂) ÷ M(NiCl₂).

n(NiCl₂) = 24.6 g ÷ 129.6 g/mol.

n(NiCl₂) = 0.19 mol; amount of nickel(II) chloride.

Na = 6.022·10²³ 1/mol; Avogadro constant.

N(NiCl₂) = n(NiCl₂) · Na.

N(NiCl₂) = 0.19 mol · 6.022·10²³ 1/mol.

N(NiCl₂) = 1.13·10²³; number of formula units.

4 0

3 years ago

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