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2 years ago

How many moles are in 25.0 grams of HF?

Chemistry

2 answers:

sasho [114]2 years ago

7 0

Answer:

Hey mate.....

Explanation:

This is ur answer.....

So, 

If one mole has a mass of 18 grams, 25 grams would have a mass of 25 grams/ 18 grams per mole or 1.39 moles.

Hope it helps!

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Aloiza [94]2 years ago

4 0

Answer:

1.39 moles............

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kap26 [50]

Answer:

Explanation:

Efficiency of the electric power plant is $e=1-\frac{T_{2}}{T_{1}}$

Here Temperature of hot source $T_{1} = 450^{o}C=450+273=723 K$

and Temperature of sink $T_{1} = 20^{o}C=20+273=293 K$

Hence the efficiency is $e=1-\frac{293}{723}=0.5947=59.47%$

Now another formula for thermal efficiency Is

$e_{therm}=\frac{Q_{1}-Q_{2}}{Q_{1}}=\frac{W}{Q_{1}}$

Here QI is the of heat taken from source 100 MJ ; Q2 of heat transferred to the sink (river) to be found

W is the of work done and W = QI -Q2

Hence From $e_{therm}=\frac{Q_{1}-Q_{2}}{Q_{1}}=\frac{W}{Q_{1}}$

$W=e(Q_{1})=(0.5947)(100)=59.47MJ$

Hence the of heat transferred to the river Is $Q_{2} -W = (100 -59.47=40.53$

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3 years ago

Student follow up

sleet_krkn [62]

Answer:

Magnesium and calcium belong to the second group i. e. alkaline earth metals. They are known as earth metals because they are extracted from the earth. They are very reactive elements. Their reactivity increases when we go from top to bottom because the outermost electrons goes farther from the nucleus i. e. atomic radius increases so less energy is needed for its removal.

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3 years ago

5. In this lab, you continued to add Reagent D to each solution until it turned blue. The purpose was to remove the oxygen to me

Basile [38]

A solution is turning blue means, it is turning it's behavior to Basic from Acidic. Reagent D must be a Basic component so it is increasing the pH of the solution. As reaction does not depend on the phase of the component, it could be anything i.e., Solid, Liquid or gas.

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3 years ago

Part 1: Name the type of chemical reaction that occurs when calcium hydroxide (Ca(OH)2) reacts with nitric acid (HNO3).

liberstina [14]

Answer:

For 1: Neutralization reaction

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Explanation:

For (1):

When a base reacts with an acid to form a salt and water molecule, it is known as a neutralization reaction. The general equation follows:

$HX+BOH\rightarrow BX+H_2O$

The chemical equation for the reaction of calcium hydroxide and nitric acid follows:

$Ca(OH)_2(aq)+2HNO_3(aq)\rightarrow Ca(NO_3)_2(aq)+2H_2O(l)$

For (2):

A single displacement reaction is defined as the reaction in which a more reactive metal displaces a less reactive metal from its salt solution. The general chemical equation follows:

$A+BX\rightarrow AX+B$

where,

Metal A is more reactive than metal B

The reactivity of metals is judged by the reactivity series where a metal lying above in the series is more reactive than the metal lying below it.

From the reactivity series below,

Zinc lies above in the series than lead thus is more reactive and will easily replace lead from its aqueous solution.

While zinc lies below in the series than calcium thus is less reactive and will not easily replace calcium from its aqueous solution.

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

$Zn(s)+CaCl_2(aq)\rightarrow \text{No reaction}$

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oksian1 [2.3K]

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