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3 years ago

Define and differentiate between accuracy and precision

1 answer:

6 0

Accuracy is the closeness of a measurement to the true value. Precision is the closeness of agreement among a set of results.

Suppose you read a refrigerator thermometer five times and get the Celsius readings 39.0, 39.3, 39.0, 39.1, and 39.0.

The average temperature is 39.1 °C. Your readings are precise because most of the readings are within 0.1 °C of the average.

However, if the actual refrigerator is 37.0 °C, your readings are not accurate because they are off by about 2°C.

If you use a thermocouple and get an average reading of 37.00, 37.03, 37.00, 37.01,and 37.00, your readings are both accurate and more precise than those from the refrigerator thermometer.

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Calculate the number of sodium ions, perchlorate ions, Cl atoms and O atoms in 17.8 g of sodium perchlorate. Enter your answers

Degger [83]

17.8 g of sodium perchlorate contains 8.73 × 10²² Na⁺ ions, 8.73 × 10²² ClO₄⁻ ions, 8.73 × 10²² Cl atoms and 3.49 × 10²³ O atoms.

First, we will convert 17.8 g of NaClO₄ to moles using its molar mass (122.44 g/mol).

$17.8 g \times \frac{1mol}{122.44g} = 0.145 mol$

Next, we will convert 0.145 moles to molecules of NaClO₄ using Avogadro's number; there are 6.02 × 10²³ molecules in 1 mole of molecules.

$0.145 mol \times \frac{6.02 \times 10^{23}molecules }{mol} = 8.73 \times 10^{22}molecules$

NaClO₄ is a strong electrolyte that dissociates according to the following equation.

NaClO₄ ⇒ Na⁺ + ClO₄⁻

The molar ratio of NaClO₄ to Na⁺ is 1:1. The number of Na⁺ in 8.73 × 10²² molecules of NaClO₄ is:

$8.73 \times 10^{22}moleculeNaClO_4 \times \frac{1 ion Na^{+} }{1moleculeNaClO_4} = 8.73 \times 10^{22}ion Na^{+}$

The molar ratio of NaClO₄ to ClO₄⁻ is 1:1. The number of ClO₄⁻ in 8.73 × 10²² molecules of NaClO₄ is:

$8.73 \times 10^{22}moleculeNaClO_4 \times \frac{1 ion ClO_4^{-} }{1moleculeNaClO_4} = 8.73 \times 10^{22}ion ClO_4^{-}$

The molar ratio of ClO₄⁻ to Cl is 1:1. The number of Cl in 8.73 × 10²² ions of ClO₄⁻ is:

$8.73 \times 10^{22}ion ClO_4^{-} \times \frac{1 atomCl }{1ion ClO_4^{-}} = 8.73 \times 10^{22}atom Cl$

The molar ratio of ClO₄⁻ to O is 1:1. The number of O in 8.73 × 10²² ions of ClO₄⁻ is:

$8.73 \times 10^{22}ion ClO_4^{-} \times \frac{4 atomO }{1ion ClO_4^{-}} = 3.49 \times 10^{23}atom O$

17.8 g of sodium perchlorate contains 8.73 × 10²² Na⁺ ions, 8.73 × 10²² ClO₄⁻ ions, 8.73 × 10²² Cl atoms and 3.49 × 10²³ O atoms.

You can learn more Avogadro's number here: brainly.com/question/13302703

8 0

2 years ago

On Earth, the mass of one of the lunar landing modules used to explore the moon was measured to be about 4,200 kg. The accelerat

Fed [463]

41,160
4,200
less than
6,860

7 0

4 years ago

Read 2 more answers

Now molecules: ____ molecules of H2 + ____ molecules of O2 → ____molecules of H2O

Valentin [98]

Answer:

4 H2 + 1 O2 = 2 H2O

6 0

4 years ago

A sample of hexane (C6H14) has a mass of 0.580 g. The sample is burned in a bomb calorimeter that has a mass of 1.900 kg and a s

Mama L [17]

Use the formula, Q= mcT

Q= heat
m= mass= 1.900Kg= 1.900 x 10^3 grams
c= specific heat= 3.21
T= 4.542 K

Q= (1.900 x10^3g)(3.21)(4.542K)= 14.6 Joules.

7 0

4 years ago

Read 2 more answers

The inner planets—Mercury, Venus, Earth, and Mars—are believed to have been formed by _____.

larisa86 [58]

i believe the answer is B :/

4 0

3 years ago