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3 years ago

Which of the following best represents both accuracy and precision

Chemistry

2 answers:

liq [111]3 years ago

6 0

Answer: Measurement B

Explanation:

Precision refers to the closeness of two or more measurements to each other.

For Example: If we measure a length three times and we get 3.5 m each time. Then the measurement is very precise.

Accuracy refers to the closeness of a measured value to a standard or known value.

For Example: If the length of the substance is 4 m and one person measures 3.9 m and another person measures 3.8 m. Then, the length measured by first person is more accurate.

Thus measurement B represents both accuracy as well as precision as the darts are close and pointed at the center.

makkiz [27]3 years ago

5 0

Accuracy is when you hit as close as to the target as you can and precision is when you are on point

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Cl2 and N2 react according to the following equation 3Cl2(g) + N2(g) rightarrow 2NCl3(g) If 4 L of a stoichiometric mixture of c

melamori03 [73]

Answer:

Volume of NCl3 is 3L

Explanation:

Avogadro states: All gases at the same volume under temperature and pressure constant have the same number of moles.

The chemical equation is:

3Cl2(g) + N2(g) → 2NCl3(g)

Where 3 moles of chlorine reacts with 1 mole of nitrogen to produce 2 moles of NCl3.

But using Avogadros law we can say:

3L of chlorine and 1L of nitrogen produce 2L of Nitrogen trichloride.

3L of chlorine and 1L of nitrogen: 4L (The stoichiometric mixture)

That means, volume of NCl3 produced is 3L

8 0

3 years ago

1826.5g of methanol (CH3OH), molar mass = 32.0 g/mol is added to 735 g of water, what is the molality of the methane 0.0348 m 1.

Snowcat [4.5K]

Answer:

Molality = 1.13 m

Explanation:

Molality is defined as the moles of the solute present in 1 kilogram of the solvent.

Given that:

Mass of $CH_3OH$ = 26.5 g

Molar mass of $CH_3OH$ = 32.04 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{26.5\ g}{32.04\ g/mol}$

$Moles\ of\ CH_3OH= 0.8271\ moles$

Mass of water = 735 g = 0.735 kg ( 1 g = 0.001 kg )

So, molality is:

$m=\frac {0.8271\ moles}{0.735\ kg}$

Molality = 1.13 m

4 0

3 years ago

Estimate ΔH for the reaction: C2H6(g) + Cl2(g)--> C2H5Cl(g) + HCl(g) given the following average bond energies (in kJ/mol): C

Leno4ka [110]

Explanation:

The reaction equation will be as follows.

$C_{2}H_{6}(g) + Cl_{2}(g) \rightarrow C_{2}H_{5}Cl(g) + HCl(g)$

Using bond energies, expression for calculating the value of $\Delta H$ is as follows.

$\Delta H = \sum B.E_{reactants} - \sum B.E_{products}$

On reactant side, from $C_{2}H_{6}$ number of bonds are as follows.

C-C bonds = 1

C-H bonds = 6

From $Cl_{2}$ ; Cl-Cl bonds = 1

On product side, from $C_{2}H_{5}Cl$ number of bonds are as follows.

C-C bonds = 1

C-H bonds = 5

C-Cl bonds = 1

From HCl; H-Cl bonds = 1

Hence, using the bond energies we will calculate the enthalpy of reaction as follows.

$\Delta H = \sum B.E_{reactants} - \sum B.E_{products}$

= $[(1 \times 348 kJ/mol) + (6 \times 414 kJ/mol) + (1 \times 242 kJ/mol)] - [(1 \times 348 kJ/mol) + (5 \times 414 kJ/mol) + (1 \times 327 kJ/mol) + (1 \times 431 kJ/mol)]$ = -102 kJ/mol

Thus, we can conclude that change in enthalpy for the given reaction is -102 kJ/mol.

5 0

3 years ago

the compound diborane can be used as a rocket propellant. what is the percent composition of boron in diborane

Blababa [14]

Answer:

78.14 % B; 21.86 % H

Step-by-step explanation:

The formula of diborane is B₂H₆.

The masses of each element are:

2B = 2 × 10.81 = 21.62 u

6H = 6 × 1.008 = 6.048 u

TOTAL = 27.67 u

% B = 21.62/27.67 × 100

= 78.14 %

% H = 6.048/ 27.67

= 21.86 %

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3 years ago

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C6H14 (g) + O2 (g) -> H20 (g) + CO2 (g) chemical reaction?

zysi [14]

Answer:

Single displacement (Substitution)

Explanation:

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2 years ago