Which best represents a homogeneous mixture of an element and a compound.

Select all that apply. Catalysts can save money by essentially lowering the:

k0ka [10]

Answer: Options (a) and (d) are the correct answer.

Explanation:

A catalyst is the substance which helps in increasing the rate of reaction.

Activation energy is the minimum amount of energy required by reactants to start the reaction. On addition of catalyst, the path of reaction changes because the energy barrier gap reduces and hence, the activation energy also decreases.

In the absence of catalyst, we need to increase the temperature so that reaction can occur quickly.

Whereas on addition of catalyst, there is no need to increase the temperature as the catalyst itself is sufficient to increase the rate of reaction. As a result, temperature should be lowered when there is addition of catalyst in the reaction.

Thus, we can conclude that catalysts can save money by essentially lowering the activation energy and temperature required.

4 0

2 years ago

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Perform the following

docker41 [41]

Answer:

8.73

Explanation:

when you are adding or subtracting numbers, the sigfig (significant figure) is based on how many numbers after the decimal. with this info, we can see that 15.67 has 2 sigfigs and 6.943 has 3 sigfigs. when you subtract normally, you would get 8.727, which has 3 sigfigs, so you would round the last 7 up to get 8.73 with 2 sigfigs!

also it is to 2 sigfigs because we know that we go by the least number of sigfigs. hope this helped!

3 0

2 years ago

What is the mass of a sample of metal that is heated from 58.8°C to 88.9°C with a

Vadim26 [7]

Answer:

$\boxed {\boxed {\sf 333 \ grams}}$

Explanation:

We are asked to find the mass of a sample of metal. We are given temperatures, specific heat, and joules of heat, so we will use the following formula.

$Q= mc \Delta T$

The heat added is 4500.0 Joules. The mass of the sample is unknown. The specific heat is 0.4494 Joules per gram degree Celsius. The difference in temperature is found by subtracting the initial temperature from the final temperature.

ΔT= final temperature - initial temperature

The sample was heated from 58.8 degrees Celsius to 88.9 degrees Celsius.

ΔT= 88.9 °C - 58.8 °C = 30.1 °C

Now we know three variables:

Q= 4500.0 J
c= 0.4494 J/g°C
ΔT = 30.1 °C

Substitute these values into the formula.

$4500.0 \ J = m (0.4494 \ J/g \textdegree C)(30.1 \textdegree C)$

Multiply on the right side of the equation. The units of degrees Celsius cancel.

$4500.0 \ J = m (13.52694 J/g)$

We are solving for the mass, so we must isolate the variable m. It is being multiplied by 13.52694 Joules per gram. The inverse operation of multiplication is division, so we divide both sides by 13.52694 J/g

$\frac {4500.0 \ J }{13.52694 J/g}= \frac{m (13.52694 J/g)}{13.52694 J/g}$

The units of Joules cancel.

$\frac {4500.0 \ J }{13.52694 J/g}= m$

$332.6694729 \ g =m$

The original measurements have 5,4, and 3 significant figures. Our answer must have the least number or 3. For the number we found, that is the ones place. The 6 in the tenth place tells us to round the 2 up to a 3.

$333 \ g \approx m$

The mass of the sample of metal is approximately 333 grams.

8 0

2 years ago

What is the molarity of a stock solution if 60 mL were used to make 150 ml of a .5M solution?

olga2289 [7]

The molarity of the stock solution is 1.25 M.

Explanation:

We have to find the molarity of the stock solution using the law of volumetric analysis as,

V1M1 = V2M2

V1 = 150 ml

M1 = 0.5 M

V2 = 60 ml

M2 = ?

The above equation can be rearranged to get M2 as,

M2 = $$\frac{V1M1}{V2}$

Plugin the values as,

M2 = $$\frac{150 \times 0.5}{60}$

= 1.25 M

So the molarity of the stock solution is 1.25 M.

4 0

2 years ago

The density of an object depends on what? Answer correctly and quick!

Dennis_Churaev [7]

Answer:

Density of a quantity of matter is its mass divided by its volume. The mass of an object depends on the atomic mass of the individual atoms or molecules and the how close the they are compressed together.

Explanation:

8 0

2 years ago

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