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3 years ago

4 physical properties of lanthanum

Chemistry

1 answer:

Assoli18 [71]3 years ago

4 0

Here are 4 physical Properties of lanthanum

its

soft

malleable

ductile

and silver white colored metal.

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Choose the number of significant figures indicated. 0.06

jeka94

One-
The 6 is the only significant figure.

8 0

3 years ago

Read 2 more answers

3. A student carries out the clay-catalyzed dehydration of cyclohexanol starting with 10 moles of cyclohexanol and obtains 500 m

IrinaK [193]

Answer:

$49.45~%$

Explanation:

In this case, we have to start with the chemical reaction:

$C_6H_1_2O~->~C_6H_1_0~+~H_2O$

So, if we start with 10 mol of cyclohexanol ( $C_6H_1_2O$ ) we will obtain 10 mol of cyclohexanol ( $C_6H_1_0$ ). So, we can calculate the grams of cyclohexanol if we calculate the molar mass:

$(6*12)+(10*1)=82~g/mol$

With this value we can calculate the grams:

$10~mol~C_6H_1_0\frac{82~g~C_6H_1_0}{1~mol~C_6H_1_0}=820~g~C_6H_1_0$

Now, we have as a product 500 mL of $C_6H_1_0$ . If we use the density value (0.811 g/mL). We can calculate the grams of product:

$500~mL\frac{0.811~g}{1~mL}=405.5~g$

Finally, with these values we can calculate the yield:

$%~=~\frac{405.5}{820}x100~=~49.45%$ %= (405.5/820)*100 = 49.45 %

See figure 1

I hope it helps!

6 0

3 years ago

How does hydrogen bonding affect water molecules

ruslelena [56]

Since the oxygen likes to hog all the electrons, it gives the hydrogen molecules a slight positive charge and the itself a slightly negative charge.
Positive attracts negative, so there is some sort of attraction between water molecules, though a weak one.

4 0

3 years ago

A container of carbon dioxide has a volume of 240 mL at a temperature of 22°C. If the pressure remains constant, what is the vol

astraxan [27]

Answer:

Volume of the $CO_{2}$ gas at 44°C is 258 ml.

Explanation

here,

using Charles' law ,

$\frac{V}{T} =\frac{v}{t}$

where , V= initial volume v= final volume

T=initial temperature t = final temperature

Given - pressure is constant ,

so , putting the values -

V= 240ml

T= 22 + 273K = 295K (since converting celsius into kelvin that

is +273K )

v =?

t = 44+ 273K = 317K

Now , putting the given values in charles' law ,

$\frac{240ml}{295K} =\frac{v}{317K}$

240ml x317K = v x 295K (through cross multiplication )

v = $\frac{240ml\times317K}{295K}$

= 258ml .

thus , the volume of carbon dioxide in a container at 44°C IS 258ml .

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3 years ago

Describe any four factors that bring out a chemical change.

Ad libitum [116K]

Answer:

Physical state of reactants

Temperature

Concentration of reactants

Presence of a catalyst

Explanation:

The larger the surface area of a reactant, the faster the rate of the reaction. If the reactant is in powdered form, the reaction takes place faster than when the reactant is in solid or block form. This is due to the fact that the latter has larger surface area

Increase in temperature causes reactant molecules to gain kinetic energy thus increasing the rate if reaction

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3 years ago