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3 years ago

What is cement and who invented it?

Chemistry

1 answer:

Sonja [21]3 years ago

5 0

Answer:

Cement is a combination of calcium, silicone, aluminum, iron and lots of other ingredients to make side walks, home made crafts, etc. The person who invented concrete is Joseph Aspdin.

Explanation:

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Using the van der Waals equation, calculate the pressure for a 1.25 mol sample of xenon contained in a volume of 1.000L at 75Â°C

alina1380 [7]

Answer:

ABC

Explanation:

hrdjyt

5 0

2 years ago

For the reaction A +B+ C D E, the initial reaction rate was measured for various initial concentrations of reactants. The follow

lora16 [44]

Answer:

Rate constant of the reaction is $3.3\times 10^{-3} M^{-2} s^{-1}$ .

Explanation:

A + B + C → D + E

Let the balanced reaction be ;

aA + bB + cC → dD + eE

Expression of rate law of the reaction will be written as:

$R=k[A]^a[B]^b[C]^c$

Rate(R) of the reaction in trail 1 ,when :

$[A]=0.30 M,[B]=0.30 M,[C]=0.30 M$

$R=9.0\times 10^{-5} M/s$

$9.0\times 10^{-5} M/s=k[0.30 M]^a[0.30 M]^b[0.30 M]^c$ ...[1]

Rate(R) of the reaction in trail 2 ,when :

$[A]=0.30 M,[B]=0.30 M,[C]=0.90 M$

$R=2.7\times 10^{-4} M/s$

$2.7\times 10^{-4} M/s=k[0.30 M]^a[0.30 M]^b[0.90 M]^c$ ...[2]

Rate(R) of the reaction in trail 3 ,when :

$[A]=0.60 M,[B]=0.30 M,[C]=0.30 M$

$R=3.6\times 10^{-4} M/s$

$3.6\times 10^{-4} M/s=k[0.60 M]^a[0.30 M]^b[0.30 M]^c$ ...[3]

Rate(R) of the reaction in trail 4 ,when :

$[A]=0.60 M,[B]=0.60 M,[C]=0.30 M$

$R=3.6\times 10^{-4} M/s$

$3.6\times 10^{-4} M/s=k[0.60 M]^a[0.60 M]^b[0.30 M]^c$ ...[4]

By [1] ÷ [2], we get value of c ;

c = 1

By [3] ÷ [4], we get value of b ;

b = 0

By [2] ÷ [3], we get value of a ;

a = 2

Rate law of reaction is :

$R=k[A]^2[B]^0[C]^1$

Rate constant of the reaction = k

$9.0\times 10^{-5} M/s=k[0.30 M]^2[0.30 M]^0[0.30 M]^1$

$k=\frac{9.0\times 10^{-5} M/s}{[0.30 M]^2[0.30 M]^0[0.30 M]^1}$

$k=3.3\times 10^{-3} M^{-2} s^{-1}$

7 0

3 years ago

For an object to sink

AfilCa [17]

Answer:

For and object to sink, it must have more density than the liquid in which it is placed. For example, if you have a glass of water and a metal spoon, the spoon will sink because it is both heavier than the water, therefore having more density.

5 0

3 years ago

What are the four most common problems that can arise in your motor design?

Nuetrik [128]

Electric motors are an essential part of our daily life as many systems, applications, and services depend on them. Motors today have a long service life and require a minimum level of maintenance to make sure that they perform efficiently. In large buildings, motors have to be maintained on a regular basis because they need to be in operation all the time; one small problem could cause a great loss to the organization.

Usually in large organizations, a motor maintenance program is carried out in which the causes of motor failures are identified and some necessary steps are taken to avoid them or lower their impact. Motors need to be inspected regularly, and other maintenance activities need to be performed to ensure efficient operation. Whenever a problem occurs, it should be corrected immediately to avoid further loss.

4 0

3 years ago

Combining a base and an acid forms

Rainbow [258]

Answer: C. Salt and Water

Explanation:

The reaction between an acid and a base will have salt and water as its end product. This process is known " Neutralization Reaction".

HCl + NaOH -----------> NaCl + H2O

Hydrochloric Sodium Sodium Water

Acid Hydroxide (base) Chloride(Salt)

4 0

2 years ago