How can a scientist make sure that the results are not a mistake in an experiment?

Below is a bar graph on candy allowance compared to the child's happiness.

rjkz [21]

Answer:

There is no bar graph attached to this question, however, the question can be answered based on the information given in the question.

The answer is A) average level of happiness

Explanation:

In an experiment, the dependent variable is the variable which is measured by the experimenter. It is the variable that responds to changes made to another variable called independent variable.

In the case of this question, it can be determined, even without the bar graph, that the experiment entails how candy allowance affects a child's happiness. Hence, the candy allowance is changed to influence or cause a response in the child's happiness, which is then measured. Therefore, the AVERAGE LEVEL OF HAPPINESS is the dependent variable.

3 0

3 years ago

A box of jello has a mass of 250 g. How many boxes must be bought to have 1 Kg of jello? *

zhuklara [117]

Answer:

Number of boxes = 4

Explanation:

Given:

Mass of one box of jello = 250 grams

Total quantity want to purchase = 1 kg = 1 × 1,000 gram = 1,000 grams

Find:

Number of boxes in 1,000 grams = ?

Computation:

Number of boxes = Total quantity want to purchase / Mass of one box of jello

Number of boxes = 1,000 / 250

Number of boxes = 4

Therefore, 4 boxes of jello must be purchase to get 1 kg of Jello.

8 0

2 years ago

*WILL GIVE BRAINLIEST*

denis-greek [22]

Weathering breaks down and loosens the surface minerals of rock so they can be transported away by agents of erosion such as water, wind and ice. There are two types of weathering: mechanical and chemical. Mechanical weathering is the disintegration of rock into smaller and smaller fragments.

3 0

2 years ago

How much water should be added to 85 mL of 0.45 M HCI to reduce the concentration to 0.20 M?

valkas [14]

Answer:

106.25 mL

Explanation:

For this, we can use

C1×V1=C2×V2

C1 = 0.45

V1 = 85

C2= 0.20

V2= ?

0.45 × 85 = 0.20 × V2

V2= (0.45 × 85)/0.20

V2=191.25mL

To find the amount of water added, subtract V1 from V2

191.25 - 85 =106.25mL

8 0

3 years ago

Determine the heat of reaction (ΔHrxn) for the combustion of ethanol (C2H5OH) by using heat of formation data: C2H5OH (l) + 3 O2

egoroff_w [7]

Answer:

$\Delta H_{rxn}=-1234.782kJ$

Explanation:

$\Delta H_{rxn}=\sum [n_{i}\times \Delta H_{f}^{0}(product)_{i}]-\sum [n_{j}\times \Delta H_{f}^{0}(reactant_{j})]$

Where $n_{i}$ and $n_{j}$ are number of moles of product and reactant respectively (equal to their stoichiometric coefficient).

$\Delta H_{f}^{0}$ is standard heat of formation.

So, $\Delta H_{rxn}=[2mol\times \Delta H_{f}^{0}(CO_{2})_{g}]+[3mol\times \Delta H_{f}^{0}(H_{2}O)_{g}]-[1mol\times \Delta H_{f}^{0}(C_{2}H_{5}OH)_{l}]-[3mol\times \Delta H_{f}^{0}(O_{2})_{g}]$

or, $\Delta H_{rxn}=[2mol\times -393.509kJ/mol]+[3mol\times -241.818kJ/mol]-[1mol\times -277.69kJ/mol]-[3mol\times 0kJ/mol]$

or, $\Delta H_{rxn}=-1234.782kJ$

4 0

3 years ago