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3 years ago

Which substances are made up of polymers?

Chemistry

2 answers:

cluponka [151]3 years ago

8 0

Polymer are made of rubber car tires

Tresset [83]3 years ago

7 0

The following are polymers

DNA : it is a polymer of nucleic acids

Protein in hair: it is a polymer of amino acids

rubber car tires: it is a polymer (it can be nylon or buna rubber etc)

ICE crystals : it is not a polymer,It is just a compound (water) in its solid phase

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A defibrillator delivers about 300 joules per shock calculate the number of calories

Tanya [424]

Answer:- 71.7 calories

Solution:- it is a unit conversion problem where we need to convert joules into calories.

The unit conversion for these energy units is:

1 calorie = 4.184 joule

The given energy is 300 joules and has to be converted to calories. We will show the set up using dimensional analysis.

$300joules(\frac{1calorie}{4.184joules})$

= 71.7 calories

So, the energy in calories is 71.7.

4 0

3 years ago

Calcium Oxide will react with ammonium chloride to produce ammonia gas, water vapor, and calcium chloride. If only 16.3 g of amm

Vaselesa [24]

Answer:

%age Yield = 22.72 %

Explanation:

The balance chemical equation is as follow;

2 NH₄Cl + CaO → 2 NH₃ + CaCl₂ + H₂O

Step 1: Calculate Moles of CaO, NH₄Cl and NH₃;

CaO:

Moles = Mass / M.Mass

Moles = 112 g / 56.07 g/mol

Moles = 1.99 moles of CaO

NH₄Cl:

Moles = Mass / M.Mass

Moles = 224 g / 53.49 g/mol

Moles = 4.18 moles of NH₄Cl

NH₃:

Moles = Mass / M.Mass

Moles = 16.3 g / 17.03 g/mol

Moles = 0.95 moles of NH₃

Step 2: Calculate Limiting reagent as:

According to equation.

2 moles of NH₄Cl reacts with = 1 mole of CaO

So,

4.18 moles of NH₄Cl will react with = X moles of CaO

Solving for X,

X = 4.18 mol × 1 mol / 2 mol

X = 2.09 mol of CaO

This means that none of the given reagent is limiting reagent. They both are almost equal in number of moles.

Step 3: Calculate Theoretical Yield of NH₃ as;

According to equation.

2 moles of NH₄Cl produced = 2 moles of NH₃

So,

4.18 moles of NH₄Cl will produce = X moles of NH₃

Solving for X,

X = 4.18 mol × 2 mol / 2 mol

X = 4.18 mol of NH₃

Step 4: Calculate Percentage Yield as;

%age Yield = Actual Yield / Theoretical Yield × 100

%age Yield = 0.95 mol / 4.18 × 100

%age Yield = 22.72 %

5 0

3 years ago

Solid cesium bromide has the same kind of crystal structure as CsCl which is pictured below: If the edge length of the unit cell

Oxana [17]

Answer:

$\mathbf {density \ d =4.4845 \ g/cm^3}$

Explanation:

Let recall the crystal structure of CsBr obtains a BCC structure. In a BCC structure, there exist only two atom per cell.

The density d of CsBr in g/cm³ can be calculated by using the formula:

$\mathtt{ density \ d = \dfrac{z \times molar\ mass \ (M)}{ edge \ length \ (a) \ \times avogadro's \ number \ (N)}}$

where;

z = 1 mole of CsBr

edge length = 428.7 pm = (4.287 × 10⁻⁸)³ cm

molar mass of CsBr = 212.81 g/mol

avogadro's number = 6.023 × 10²³

$\mathtt{ density \ d = \dfrac{1 \times 212.81}{(4.287 \times 10^{-8})^3 \times 6.023 \times 10^{23}}}$

$\mathtt{ density \ d = \dfrac{ 212.81}{47.4540533}}$

$\mathbf {density \ d =4.4845 \ g/cm^3}$

5 0

3 years ago

Name the four types of friction. Provide one example not used in your lesson for each type.

Bond [772]

Friction is the force that opposes motion between any surfaces that are in contact. There are four types of friction: static, sliding, rolling, and fluid friction. Static, sliding, and rolling friction occur between solid surfaces.

5 0

3 years ago

Calculate the mass percent of HOCH 2CH 2OH in a solution made by dissolving 3.2 g of HOCH 2CH 2OH in 43.5g of water.

grin007 [14]

Answer:

$\%m/m=6.85\%$

Explanation:

Hello,

In this case, we are asked to compute the by mass percent for the given 3.2 g of ethylene glycol in 43.5 g of water. In such a way, since the by mass percent is computed as follows:

$\%m/m=\frac{m_{solute}}{m_{solute}+m_{solvent}} *100\%$

Whereas the solute is the ethylene glycol and the solvent the water, therefore we obtain:

$\%m/m=\frac{3.2g}{3.2g+43.5g} *100\%\\\\\%m/m=6.85\%$

Best regards.

5 0

3 years ago