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3 years ago

#1: Which type of substance is an electron-pair donor?

1 answer:

7 0

Answer is: D. Lewis base.
Lewis acid is a chemical element, molecule or ion that contains an empty orbital which is capable of accepting an electron pair from a Lewis base. A Lewis base is element, molecule or ion that has a filled orbital and has electron pair which is not involved in bonding and can give it to Lewis acid. Lewis base is for example ammonia (NH3).

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Based on the visible light spectrum, which of the following has the longest wavelength?

bezimeni [28]

Answer:

I think the answer is D a ray of violet light

Hope it helps!

7 0

3 years ago

Read 2 more answers

What is true at stp? A)the temperature is 273.15 kelvin, B)one mole of gas occupies one liter of volume. C)pressure is at 101 vo

fgiga [73]

STP stands for standard temperature and pressure. Standard pressure is equivalent to 1 atm, and standard temperature is equivalent to 273.15 K. Therefore, your answer is A. the temperature is 273.15 kelvin.

Hope this helps!

3 0

3 years ago

Classify the following as an element, compound, homogeneous mixture, or heterogeneous

Archy [21]

The answer is D. Heterogeneous mixture

3 0

3 years ago

Calculate ΔH for the reaction: C(graphite) + 2H 2(g) + 1/2 O 2(g) => CH 3OH(l) Using the following information: C(graphite) +

Alika [10]

Answer:

$\Delta H$ for the given reaction is -238.7 kJ

Explanation:

The given reaction can be written as summation of three elementary steps such as:

$C(graphite)+O_{2}(g)\rightarrow CO_{2}(g)$ $\Delta H_{1}= -393.5 kJ$

$2H_{2}(g)+O_{2}(g)\rightarrow 2H_{2}O(l)$ $\Delta H_{2}= (2\times -285.8)kJ$

$CO_{2}(g)+2H_{2}O(l)\rightarrow CH_{3}OH(l)+\frac{3}{2}O_{2}(g)$ $\Delta H_{3}= 726.4 kJ$

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$C(graphite)+2H_{2}(g)+\frac{1}{2}O_{2}(g)\rightarrow CH_{3}OH(l)$

$\Delta H=\Delta H_{1}+\Delta H_{2}+\Delta H_{3}=-238.7 kJ$

4 0

3 years ago

When magnesium reacts with hydrochloric acid, hydrogen gas is formed: 2HCl + Mg → H2 + MgCl2. What is the volume of hydrogen pro

Maksim231197 [3]

Answer:- C. 16.4 L

Solution:- The given balanced equation is:

$2HCl+Mg\rightarrow H_2+MgCl_2$

From this equation, there is 2:1 mol ratio between HCl and hydrogen gas. First of all we calculate the moles of hydrogen gas from given grams of HCl using stoichiometry and then the volume of hydrogen gas could be calculated using ideal gas law equation, PV = nRT.

Molar mass of HCl = 1.008 + 35.45 = 36.458 gram per mol

The calculations are shown below:

$49.0gHCl(\frac{1molHCl}{36.458gHCl})(\frac{1molH_2}{2molHCl})$

= $0.672molH_2$

Now we will use ideal gas equation to calculate the volume.

n = 0.672 mol

T = 25 + 273 = 298 K

P = 101.3 kPa = 1 atm

R = $0.0821\frac{atm.L}{mol.K}$

PV = nRT

1(V) = (0.672)(0.0821)(298)

V = 16.4 L

From calculations, 16.4 L of hydrogen gas are formed and so the correct choice is C.

7 0

3 years ago