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3 years ago

How many grams of ethylene glycol (c2h6o2 must be added to 1.25 kg of water to produce a solution that freezes at -5.88 ∘c?

1 answer:

6 0

The freezing point depression is calculated through the equation,
ΔT = (kf) x m
where ΔT is the difference in temperature, kf is the freezing point depression constant (1.86°C/m), and m is the molality. Substituting the known values,
5.88 = (1.86)(m)
m is equal to 3.16m

Recall that molality is calculated through the equation,
molality = number of mols / kg of solvent
number of mols = (3.16)(1.25) = 3.95 moles
Then, we multiply the calculated amount in moles with the molar mass of ethylene glycol and the answer would be 244.9 g.

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If you start with 30 moles of O2, how many moles of SiO2 can you make?

Ivanshal [37]

Answer:

30moles of SiO₂

Explanation:

Given parameters:

Number of moles of O₂ = 30moles

Unknown:

Number of moles of SiO₂ = ?

Solution:

To solve this problem, we need to write the reaction expression:

Si + O₂ → SiO₂

The reaction is balanced;

1 mole of O₂ will produce 1 mole of SiO₂

30mole of O₂ will produce 30moles of SiO₂

7 0

3 years ago

Identify whether longhand notation or noble-gas notation was used in each case below.

n200080 [17]

Answer:

The given electronic configuration is long hand notation.

Explanation:

Long-hand notation of representing electronic configuration is defined as the arrangement of total number of electrons that are present in an element.

Noble-gas notation of representing electronic configuration is defined as the arrangement of valence electrons in the element. The core electrons are represented as the previous noble gas of the element that is considered.

The given electronic configuration of potassium (K):

The above configuration has all the electrons that are contained in the nucleus of an element. Thus, this configuration is a long-hand notation.

6 0

3 years ago

How many milligrams of AgNO3 is required to completely react with 81.5 mg LiOH?

BartSMP [9]

Answer:

$m_{AgNO_3}=577.6mg$

Explanation:

Hello there!

In this case, according to the given chemical reaction, it is first necessary to compute the moles of reacting LiOH given its molar mass:

$n_{LiOH}=81.5mg*\frac{1g}{1000mg}*\frac{1mol}{23.95g} =0.0034molLiOH$

Thus, since there is a 1:1 mole ratio between lithium hydroxide and silver nitrate (169.87 g/mol) the resulting milligrams turn out to be:

$m_{ AgNO_3}=0.0034molLiOH*\frac{1molAgNO_3}{1molLiOH} *\frac{169.87gAgNO_3}{1molAgNO_3} *\frac{1000gAgNO_3}{1gAgNO_3} \\\\m_{AgNO_3}=577.6mg$

Best regards!

7 0

2 years ago

How many grams of carbon dioxide are produced from the combustion of 250.G of ethane, C3H8 in the reaction C3H8 +5O2 - 3CO2 +4H2

ludmilkaskok [199]

Answer:

750 g of CO₂

Explanation:

The balanced equation for the reaction is given below:

C₃H₈ + 5O₂ —> 3CO₂ + 4H₂O

Next, we shall determine the mass of C₃H₈ that reacted and the mass of CO₂ produced from the balanced equation. This can be obtained as follow:

Molar mass of C₃H₈ = (12×3) + (8×1)

= 36 + 8 = 44 g/mol

Mass of C₃H₈ from the balanced equation = 1 × 44 = 44 g

Molar mass of CO₂ = 12 + (16×2)

= 12 + 32 = 44 g/mol

Mass of CO₂ = 3 × 44 = 132 g

SUMMARY:

From the balanced equation above,

44 g of C₃H₈ reacted to produce 132 g of CO₂.

Finally, we shall determine the mass of CO₂ produced by the reaction of 250 g of C₃H₈. This can be obtained as follow:

From the balanced equation above,

44 g of C₃H₈ reacted to produce 132 g of CO₂.

Therefore, 250 g of C₃H₈ will react to produce = (250 × 132)/44 = 750 g of CO₂.

Thus, 750 g of CO₂ were obtained from the reaction.

8 0

3 years ago

A beaker has a volume of .550L. What is it in milliliters?

Vladimir [108]

Add 3 zeros at the end to convert to milliliters.
550,000 milliliters.

6 0

3 years ago