1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
vodomira [7]
3 years ago
9

Help please guys!

Chemistry
1 answer:
ra1l [238]3 years ago
7 0
<span>Yes, mass is conserved. When sodium hydroxide (clear solution) and copper sulfate (blue solution) are mixed, they form a copper hydroxide (a blue solid) and sodium sulfate (a clear solution). This can be tested simply. First weigh the masses (10 g and 57 g, which totals 67 g)) of the two starting solutions prior to mixing. Then mix and allow the reaction to occur and weigh the mass of the mixture (10g + 57 g = 67 g). The two solutions should have the same mass and therefore demonstrate conservation of mass.</span>
You might be interested in
What element is [Kr]5s24d105p2
GenaCL600 [577]
Iodine would be your answer!!!
5 0
3 years ago
What are the two types of numbers in experimental calculations?
FinnZ [79.3K]
The logistics of a proposed larger study

Gain familiarity with the experimental material,

Ensure that treatments are not obviously excessively mild or severe

Check that staff are sufficiently well trained in the necessary procedures

Ensure that all steps in a proposed future experiment are feasible.

Gain some information on variability, although this will not usually be sufficiently reliable to form the basis of power analysis calculations of sample size.

Exploratory experiments can be used to generate data with which to develop hypotheses for future testing. They may “work” or “not work”. They may have no clearly stated hypothesis (“let’s see what happens if..” is not a valid hypothesis on which to base an experiment).

Often they will measure many outcomes (characters). Picking out “interesting looking differences” (known as data snooping) and then doing a hypothesis test to see if the differences are statistically significant will lead to serious overestimation of the magnitude of a response and excessive numbers of false positive results. Such differences should always be tested in a controlled experiment where the hypothesis is stated a priori before the results are published.

Depending on the nature of the data, statistical analysis will often be done using an analysis of variance (ANOVA)

Confirmatory experiments are used to test some relatively simple hypothesis stated a priori. This is the type of experiment mainly considered in this web site.

The basic principles are:

Experiments involve comparisons between two or more groups

Their aim is to test a “null hypothesis” that there is no difference among the groups for the specified outcome.

If the null hypothesis is rejected at a certain level of probability (often 5%) this means that the probability of getting a result as extreme as this or more extreme in the absence of a true effect is 5% (assuming also that the experiment has been properly conducted). So it is assumed that such a difference is likely to be the result of the treatment. But, it could be a false positive resulting from sampling variation.

Failure to reject the null hypothesis does not mean that the treatment has no effect, only that if there is a real effect this experiment failed to detect it. “Absence of evidence is not evidence of absence”.

Experimental subjects need to be independently replicated because individuals (of whatever type) vary. Two subjects can normally be regarded as being independent if they can theoretically receive different treatments.

Subjects need to be assigned to groups, held in the animal house and measured at random in order to minimise the chance of bias (a systematic difference between groups)

As far as possible the experimenter should be “blind” with respect to the treatment group in order to minimise bias.

The experiments need to be powerful, i.e. they should have a high probability of detecting an effect of clinical or scientific importance if it is present.

In many cases a formal experimental designsuch as a “completely randomised”, “randomised block”, “Latin square” etc. design will be used.

In most cases it is useful if the experiment has a wide range of applicability. In other words the results should hold true under a range of different conditions (different strains, both sexes, different diets, different environments etc.). At least some of these factors should be explored using factorial and randomised block designs.

Experiments to explore relationships between variables. A typical example would be a growth curve or a dose-response relationship. In these experiments the aim is often to test whether the two variables are associated, and if so, what is the nature of that relationship. The typical statistical analysis involves correlation and/or regression.

 


8 0
3 years ago
Consider the hypothetical reaction 4A + 3B → C + 2D Over an interval of 3.00 s the average rate of change of the concentration o
pogonyaev

Answer:

Final concentration of C at the end of the interval of 3s if its initial concentration was 3.0 M, is 3.06 M and if the initial concentration was 3.960 M, the concentration at the end of the interval is 4.02 M

Explanation:

4A + 3B ------> C + 2D

In the 3s interval, the rate of change of the reactant A is given as -0.08 M/s

The amount of A that has reacted at the end of 3 seconds will be

0.08 × 3 = 0.24 M

Assuming the volume of reacting vessel is constant, we can use number of moles and concentration in mol/L interchangeably in the stoichiometric balance.

From the chemical reaction,

4 moles of A gives 1 mole of C

0.24 M of reacted A will form (0.24 × 1)/4 M of C

Amount of C formed at the end of the 3s interval = 0.06 M

If the initial concentration of C was 3 M, the new concentration of C would be (3 + 0.06) = 3.06 M.

If the initial concentration of C was 3.96 M, the new concentration of C would be (3.96 + 0.06) = 4.02 M

3 0
3 years ago
Consider the genetic cross for absent-mindedness, which is a dominant trait. What is the probability that the offspring of this
4vir4ik [10]
D)100%

Every single one has the dominate gene so all the offspring will get it

I hope that helps!
8 0
3 years ago
Read 2 more answers
The DEA has designated five chemicals often found in spice as _____ controlled substances, making it illegal to sell, buy, or po
Mrrafil [7]

Answer:

I'm pretty sure this doesn't really connect with chemistry much but the answer should be <u>Schedule 1 </u> as stated by the Drug enforcement agency.

4 0
3 years ago
Other questions:
  • The specific heat of mercury is 380 j/kg/k. How much energy is required to raise the temperature of 42g of mercury from 25°C to
    5·1 answer
  • Alice added sodium chloride to water and stirred the water for several minutes. Alice is most likely trying to demonstrate that
    14·1 answer
  • Help me with 15 16 17 and 18 please thank you so much
    15·2 answers
  • Describe how magnetic forces and electric forces are similar and different from each other
    15·1 answer
  • An automobile tire at 30°C has a pressure of 3.00 atm. Temperature decreases to -5°C. Assume that there is no volume change in t
    13·2 answers
  • Cl2(g) + 2kbr(aq)= 2kcl(aq) + Br2(I)
    10·1 answer
  • Which of the following statements about weathering is false?
    6·2 answers
  • John and Lisa collected a sample of ocean water and placed it in a jar. Within a couple of days, the water had evaporated and sa
    11·1 answer
  • Question 3
    9·1 answer
  • an oven adds 2260 j heat to a zinc tray that weighs 195g of the tray starts at 25 what is the final temperature of the tray
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!