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2 years ago

The accepted value is 1.43. Which correctly describes this student’s experimental data?

Chemistry

2 answers:

Yuliya22 [10]2 years ago

7 0

Answer: neither accurate nor precise

Explanation:

Accuracy is defined as how close the measured value is to a standard value. For example if the given volume of water is 20 ml and the two measured values are 19 ml and 18 ml then the former measured value is more accurate than the later.

Precision is defined as how measured values are close to each other. For example, if the length of the wire of 10 m. If the first person measures the length of the same wire thrice and got values 9.7, 9.8 and 9.75 m whereas the second person got values 9.5 , 9.6 and 9.8. In such a case the first person’s measured value is more precise.

Thus as the accepted value is 1.43 and measured values are 1.29 , 1.93 and 0.88 , the experimental data is neither accurate nor precise.

Natalija [7]2 years ago

4 0

Answer:

Neither accurate nor precise

Explanation:

The values were not near or even the same as the accepted value thus making it neither accurate nor precise.

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In a voltaic cell made of a Ag strip and an Al strip immersed in 1.0 M aqueous AgNO_3 and Al(NO_3)_3 solutions, respectively, wi

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Answer:

When the operation of the voltaic cell, which is formed of an aluminum and silver strip takes place, the atom of aluminum loses three of its electrons and the Al3+ formed moves within the solution. The Al3+ ion gets dissolved within the solution and the electrons lost in the process moves through the wire and get acquired by the ions of silver, which then get reduced to solid Ag resulting in the mass gain of silver strip.

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2 years ago

A student has 7.05 g of zinc powder, 1.60 L of a 3.40 M calcium nitrate solution, and 1.50 L of a 1.60 M lead(II) nitrate soluti

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<u>Answer:</u> Zinc will react with lead (II) nitrate solution.

<u>Explanation:</u>

Single displacement reaction is defined as the reaction in which more reactive element displaces a less reactive element from its chemical reaction.

The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.

General equation for single displacement reaction follows:

$A+BC\rightarrow AC+B$

When zinc is reacted with calcium nitrate, the reaction does not take place as zinc is less reactive than calcium. Zinc lies below in the series than calcium.

$Zn+Ca(NO_3)_2\rightarrow \text{No reaction}$

But, when zinc is reacted with lead (II) nitrate, the reaction do take place as zinc is more reactive than lead. Zinc lies above in the series than lead.

The chemical equation for the reaction of zinc and lead (II) nitrate follows:

$Zn+Pb(NO_3)_2\rightarrow Zn(NO_3)_2+Pb$

Hence, zinc will react with lead (II) nitrate solution.

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2 years ago

Magnesium reacts with iron(III) chloride to form magnesium chloride (which can be used in fireproofing wood and in disinfectants

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Answer:

154.0831 g

Explanation:

The formula for the calculation of moles is shown below:

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

Given: For $Mg$

Given mass = 41.0 g

Molar mass of $Mg$ = 24.31 g/mol

Moles of $Mg$ = 41.0 g / 24.31 g/mol = 1.6865 moles

Given: For $FeCl_3$

Given mass = 175 g

Molar mass of $FeCl_3$ = 162.2 g/mol

Moles of $FeCl_3$ = 175 g / 162.2 g/mol = 1.0789 moles

According to the given reaction:

$3Mg_{(s)}+2FeCl_3_{(s)}\rightarrow 3MgCl_2_{(s)}+2Fe_{(s)}$

3 moles of Mg react with 2 moles of $FeCl_3$

1 mole of Mg react with 2/3 moles of $FeCl_3$

1.6865 mole of Mg react with (2/3)*1.6865 moles of $FeCl_3$

Moles of $FeCl_3$ = 1.1243 moles

Available moles of $FeCl_3$ = 1.0789 moles

Limiting reagent is the one which is present in small amount. Thus, $FeCl_3$ is limiting reagent. (1.0789 < 1.1243)

The formation of the product is governed by the limiting reagent. So,

2 moles of $FeCl_3$ gives 3 moles of magnesium chloride

1 mole of $FeCl_3$ gives 3/2 moles of magnesium chloride

1.0789 mole of $FeCl_3$ gives (3/2)*1.0789 moles of magnesium chloride

Moles of magnesium chloride = 1.61835 moles

Molar mass of magnesium chloride = 95.21 g/mol

Mass of magnesium chloride = Moles × Molar mass = 1.61835 × 95.21 g = 154.0831 g

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2 years ago

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Answer is: volume of KBr is 357 mL.
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m(KBr) = 30,5 g.
n(KBr) = m(KBr) ÷ M(KBr).
n(KBr) = 30,5 g ÷ 119 g/mol.
n(KBr) = 0,256 mol.
V(KBr) = n(KBr) ÷ c(KBr).
V(KBr) = 0,256 mol ÷ 0,716 mol/L.
V(KBr) = 0,357 L · 1000 mL/L = 357 mL.

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