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3 years ago

How efficient are electric engines

Chemistry

1 answer:

raketka [301]3 years ago

3 0

Answer:

Electric engines have efficiencies of roughly 90% whilst combustion engines about 10% to 30%. This is because combustion engines emit much more heat, which is always energy that is not used as work, and thus increases inefficiency.

Explanation:

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How many formula units make up 24.2 g of magnesium chloride (MgCl2)?<br><br> Help!!

NNADVOKAT [17]

Answer:

Approximately $1.53 \times 10^{23}$ formula units ( $0.254\; \rm mol$ ).

Explanation:

Refer to a modern periodic table for the relative atomic mass of magnesium ( $\rm Mg$ ) and chlorine ( $\rm Cl$ ):

$\rm Mg$ : $24.305$ .
$\rm Cl$ : $35.45$ .

In other words, the mass of $1\; \rm mol$ of $\rm Mg$ atoms would be (approximately) $24.305\; \rm g$ .

Likewise, the mass of $1\; \rm mol$ of $\rm Cl$ atoms would be approximately $35.45\; \rm g$ .

One formula unit of the ionic compound $\rm MgCl_{2}$ includes exactly as many atoms as there are in the given formula. The formula mass of a compound is the mass of $1\; \rm mol$ of the formula units of this compound.

The formula $\rm MgCl_{2}$ includes one $\rm Mg$ atom and two $\rm Cl$ atoms.

Hence, every formula unit of $\rm MgCl_{2} \!$ would include the same number of atoms: one $\rm Mg\!$ atom and two $\rm Cl\!$ atoms. There would be $1\; \rm mol$ of $\rm Mg$ atoms and $2\; \rm mol$ of $\rm Cl$ atoms in $1\; \rm mol\!$ of $\rm MgCl_{2}$ formula units.

Thus, the mass of $1\; \rm mol\!$ of $\rm MgCl_{2}$ formula units would be equal to the mass of $1\; \rm mol$ of $\rm Mg$ atoms plus the mass of $2\; \rm mol$ of $\rm Cl$ atoms. (The mass of $1\; \rm mol\!\!$ of each atom could be found from the relative atomic mass of each element.)

$\begin{aligned}& M({\rm MgCl_{2}}) \\ =\; & 24.305\; {\rm g \cdot mol^{-1}} + 2\times {\rm 35.45 \; \rm g \cdot mol^{-1}} \\ =\; & 95.205\; \rm g \cdot mol^{-1}\end{aligned}$ .

In other words, the formula mass of $\rm MgCl_{2}$ is $95.205\; \rm g \cdot mol^{-1}$ .

Therefore, the number of formula units in $m = 24.2\; \rm g$ of $\rm MgCl_{2}$ would be:

$\begin{aligned}n &= \frac{m({\rm MgCl_{2}})}{M({\rm MgCl_{2}})} \\ &= \frac{24.2\; \rm g}{95.205\; \rm g\cdot mol^{-1}} \\ & \approx 0.254\; \rm mol\end{aligned}$ .

Multiple $n$ by Avogadro's Number $N_{A} \approx 6.022 \times 10^{23}\; \rm mol^{-1}$ to estimate the number of formula units in $0.254\; \rm mol$ :

$\begin{aligned}N &= n \cdot N_{A} \\ &\approx 0.254\; \rm mol \times 6.022 \times 10^{23}\; \rm mol^{-1} \\ &\approx 1.53\times 10^{23}\end{aligned}$ .

6 0

2 years ago

Which are examples of habitat destruction? Check all that apply

RSB [31]

An example of habitat destruction could be a squirrel who lives in a tree but modern civilication cutting down the squirrels tree and leaving it homeless

5 0

2 years ago

Read 2 more answers

How many grams are in 0.572 moles of glucose, C6H12O6

LUCKY_DIMON [66]

Answer:

103.00

Explanation:

1 mole of Glucose

6 C = 6 * 12 = 72 grams

12H = 12 * 1 = 12 grams

6O = 6 * 16 =96 grams

Total = 180 grams

0.572 moles of Glucose

1 mol of glucose = 180 grams

0.572 mols of glucose = x

x = 0.572 * 180

x = 103.00 grams

6 0

2 years ago

If 21.5 mol of an ideal gas is at 9.65 atm at 10.90 ∘C, what is the volume of the gas?

mamaluj [8]

<h3>Answer:</h3>

51.93 L

<h3>Explanation:</h3>

From the question we are given the following components of an ideal gas;

Number of moles = 21.5 mol

Pressure, P = 9.65 atm

Temperature, T = 10.90°C, but K= °C + 273.15

=284.05 k

We are required to calculate the volume of the ideal gas.

We are going to use the ideal gas equation which is given by;

PV = nRT, where P, V, T and n are the pressure, volume, temperature and moles of the ideal gas respectively. R is the ideal gas constant, 0.082057 L.atm/mol.K

To get the volume, we rearrange the formula to get;

V = nRT ÷ P

= (21.5 × 0.082057 × 284.05 K) ÷ 9.65 atm

= 51.93 L

Thus, the volume of the ideal gas is 51.93 L

3 0

2 years ago

Can you please solve this question???

Mandarinka [93]

Answer:

1 is Argon

2 is Kalium

3 is Calcium

ii)

Y belongs to alkaline metals

Z belongs to alkaline earth metals

iii)

Kalium (Y) is alkaline metal

8 0

2 years ago