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2 years ago

What type of energy changes take place when a candle burns

2 answers:

8 0

This would be chemical energy that is converted to heat. The heat from the wick melts the wax which gets absorbed in the wick and then gets burnt (which is really oxidation) to produce heat energy as well as light energy.

frutty [35]2 years ago

7 0

The two types of energy changes that occur are heat and light changes.

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Which of the following is the main function of the Circulatory System?

kolbaska11 [484]

Answer:

B: The transport oxygen and nutrients around your body and help to get rid of wastes

Explanation:

The circulatory system carries oxygen and nutrients to the body, but it can also help get rid of waste (though that isn't a huge function of it).

8 0

2 years ago

A chemist must prepare 300.0mL of nitric acid solution with a pH of 0.70 at 25°C. He will do this in three steps: Fill a 300.0mL

d1i1m1o1n [39]

<u>Answer:</u> The volume of concentrated solution required is 9.95 mL

<u>Explanation:</u>

To calculate the pH of the solution, we use the equation:

$pH=-\log[H^+]$

We are given:

pH = 0.70

Putting values in above equation, we get:

$0.70=-\log[H^+]$

$[H^+]=10^{-0.70}=0.199M$

1 mole of nitric acid produces 1 mole of hydrogen ions and 1 mole of nitrate ions.

Molarity of nitric acid = 0.199 M

To calculate the volume of the concentrated solution, we use the equation:

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the molarity and volume of the concentrated nitric acid solution

$M_2\text{ and }V_2$ are the molarity and volume of diluted nitric acid solution

We are given:

$M_1=7.0M\\V_1=?mL\\M_2=0.199M\\V_2=350mL$

Putting values in above equation, we get:

$7.0\times V_1=0.199\times 350.0\\\\V_1=\frac{0.199\times 350}{7.0}=9.95mL$

Hence, the volume of concentrated solution required is 9.95 mL

6 0

2 years ago

Complete each of the definitions with the appropriate phrase. Precision means that measurements are close to Accuracy means that

sergiy2304 [10]

Answer: Precision means that measurements are close to each other . Accuracy means that measurements are close to accepted value

Explanation:

Precision refers to the closeness of two or more measurements to each other.

For Example: If we weigh a given substance five times and you get 5.0 kg each time. Then the measurement is very precise.

Accuracy refers to the closeness of a measured value to a standard or known value.

For Example: If the mass of a substance is 5.0 kg and one person weighed 4.9 kg and another person weighed 3.9 kg. Then, the weight measured by first person is more accurate.

Thus Precision means that measurements are close to each other . Accuracy means that measurements are close to accepted value.

5 0

2 years ago

During glycolysis, for every 6 moles of glucose that enter the pathway, how many moles of atp are used? how many moles atp are g

Goryan [66]

During the process of glycolysis 1 mole of glucose yields 2 pyruvic acid. In the process 2 ATPs molecules are used up and 4 other ATP molecules are produced by substrate level phosphorylation and 2 NADH are also produced. Therefore; for six moles of glucose; 12 ATP molecules will be used up, 24 ATP molecules will be generated, 12 moles of NADH will be used and 12 moles of pyruvate are made.

7 0

2 years ago

The students in the picture below are using a globe and a lamp to model the Sun and the Earth. If the model Earth acts the same

timofeeve [1]

Answer:

The only one that makes sense IF the model behaves as the Earth is D.

Explanation:

7 0

3 years ago