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3 years ago

Emily spills concentrated sodium hydroxide solution on her lab bench. What she should do first?

Chemistry

1 answer:

blagie [28]3 years ago

4 0

<h2>Answer:</h2>

She should notify her teacher.

<h2>Explanation:</h2>

Sodium Hydroxide is very corrosive in nature and it causes Redness, Pain, Serious skin burns and Blisters. Sodium hydroxide does not produce systemic toxicity, but is very CORROSIVE and can cause severe burns in all tissues that it comes in contact with. Therefore she should not touch it and she must notify her teacher as soon as possible.

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Does the temperature of water affect how fast salt dissolves

gulaghasi [49]

Yes just like with sugar and water temperature affects the process and warmer water causes faster dissolution.

5 0

4 years ago

How many moles of carbon are there in 5 g of carbon?

Umnica [9.8K]

Answer:

0.416666667

Explanation:

number of moles= mass of sample ÷ molar mass

=5÷12

=0.41666667

8 0

3 years ago

The density of a certain type of plastic is 0.81 g/cm3. If a sheet of this plastic is 10.0 m long, 1.0 m wide, and 1 cm thick, w

crimeas [40]

<u>Answer:</u> The mass of plastic sheet is $8.1\times 10^4g$

<u>Explanation:</u>

The plastic sheet is in the form of cuboid. To calculate the volume of cuboid, we use the equation:

$V=lbh$

where,

V = volume of cuboid

l = length of cuboid = 10.0 m = 1000 cm (Conversion factor: 1 m = 100 cm)

b = breadth of cuboid = 1.0 m = 100 cm

h = height of cuboid = 1 cm

Putting values in above equation, we get:

$V=1000\times 100\times 1=10^5cm^3$

To calculate mass of a substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

We are given:

Density of plastic sheet = $0.81g/cm^3$

Volume of plastic sheet = $10^5cm^3$

Putting values in equation 1, we get:

$0.81g/cm^3=\frac{\text{Mass of plastic sheet}}{10^5cm^3}\\\\\text{Mass of plastic sheet}=8.1\times 10^4g$

Hence, the mass of plastic sheet is $8.1\times 10^4g$

8 0

3 years ago

Determines the mass of the atom

Marizza181 [45]

Answer:

No of neutrons and protons decides mass of the atom. Electrons having negligible

mass are ignored.

Mass of atom

Mass of atom= sum of no of protons(Z) and neutons(N)

=Z+N

For eg:

In hydrogen atom,

Mass of H= Z+N

=1+0

=1 AMU

5 0

3 years ago

Calculate the standard heat of reaction for the following methane-generating reaction of methanogenic bacteria: 4CH3NH2(g) + 2H2

PIT_PIT [208]

<u>Answer:</u> The standard heat for the given reaction is -138.82 kJ

<u>Explanation:</u>

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles.

The equation used to calculate enthalpy change is of a reaction is:

$\Delta H^o_{rxn}=\sum [n\times \Delta H_f_{(product)}]-\sum [n\times \Delta H_f_{(reactant)}]$

For the given chemical reaction:

$4CH_3NH_2(g)+2H_2O(l)\rightarrow 3CH_4(g)+CO_2(g)+4NH_3(g)$

The equation for the enthalpy change of the above reaction is:

$\Delta H_{rxn}=[(3\times \Delta H_f_{(CH_4(g))})+(1\times \Delta H_f_{(CO_2(g))})+(4\times \Delta H_f_{(NH_3(g))})]-[(4\times \Delta H_f_{(CH_3NH_2(g))})+(2\times \Delta H_f_{(H_2O(l))})]$

We are given:

$\Delta H_f_{(H_2O(l))}=-285.8kJ/mol\\\Delta H_f_{(NH_3(g))}=-46.1kJ/mol\\\Delta H_f_{(CH_4(g))}=-74.8kJ/mol\\\Delta H_f_{(CO_2(g))}=-393.5kJ/mol\\\Delta H_f_{(CH_3NH_2(g))}=-22.97kJ/mol$

Putting values in above equation, we get:

$\Delta H_{rxn}=[(3\times (-74.8))+(1\times (-393.5))+(4\times (-46.1))]-[(4\times (-22.97))+(2\times (-285.8))]\\\\\Delta H_{rxn}=-138.82kJ$

Hence, the standard heat for the given reaction is -138.82 kJ

3 0

3 years ago