B. kilometers
C. millimeters
D. centimeters
Answer:
The answer is C
Explanation:
Precision generally means been accurate (and can be loosely interpreted to mean been exact). Length is averagely measured in meters. However, in order to get the actual length of a substance using a tape, millimeters give the most accurate length (of all the options) as it provides the length to the smallest details (of all the options provided). The illustration below shows the relationship between millimeters and the rest of the options.
while 1 kilometer = 1000 meters
1 meter = 100 centimeters
1 centimeter = 10 millimeters
From the relationship above, millimeters is clearly the most precise of all the options provided.
B. If I add substance X, then it will lower the temperature at which water freezes.
C. People should eat vegetables.
D. Bananas are better for you than chocolate. 2: Kobe is testing whether 100 g of substance A, 100 g of substance B, or 100 g of substance C produces more oxygen in a chemical reaction at 25°C. What is the independent variable?
A. the masses of the substances
B. the temperature of the substances
C. the amount of oxygen produced
D. the nature of the substances 3: A chemist measures the amount of mercury in sediment samples from three areas of a river (the source, the midway point, and the mouth). Which of the following is the most reasonable hypothesis for the chemist's experiment?
A. If a chemical plant near the source of the river is dumping mercury, then the mercury levels should be highest at the source and lowest at the mouth.
B. If a chemical plant near the source of the river is dumping mercury, then the mercury levels should be highest at the mouth and lowest at the midway point.
C. If a chemical plant near the source of the river is dumping mercury, then the mercury levels should be highest at the mouth and lowest at the source.
D. If a chemical plant near the source of the river is dumping mercury, then the mercury levels should be the same all along the river.
The correct options are as follows:
1. B.
In scientific investigation, an hypothesis refers to a supposition that is put forward to explain an observed phenomenon. A hypothesis is described as valid if it fulfilled five different conditions. The conditions are as follows:
1. It must be capable of empirical verification.
2. It must be express clearly and it must be definite and certain.
3. It must be specific and it is predictions must be clearly expressed.
4. It must be formulated in such a way that its content can easily be translated to understand the observed phenomenon that give birth to the hypothesis.
5. It should possess theoretical relevance.
2. D.
Scientific investigations usually make use of two major variables, these are dependent variables an independent variables. The dependent variable refers to the variable whose value depend on that of another variable. The independent variable on the other hand refers to that variable whose variation does not depend on the value of another variable. In the question given above, the natures of the three substances is the independent variable because their variation is not determined by any variable.
3. B.
If a chemical plant near the source of a water body is dumping mercury inside the water, then the highest amount of mercury will be found at the mouth of the river while the lowest quantity of mercury will be found at the middle of the water. This is because as the water waves are carrying the mercury deposits away from the mouth of the river, they will disperse it evenly in the river and thus its concentration will reduce compare to that present at the mouth of the river. The highest amount of mercury is found at the mouth of the river because that is where the mercury enters the water.
Answer:
10 g
Explanation:
Right from the start, just by inspecting the values given, you can say that the answer will be
10 g
.
Now, here's what that is the case.
As you know, a substance's specific heat tells you how much heat is needed to increase the temperature of
1 g
of that substance by
1
∘
C
.
Water has a specific heat of approximately
4.18
J
g
∘
C
. This tells you that in order to increase the temperature of
1 g
of water by
1
∘
C
, you need to provide
4.18 J
of heat.
Now, how much heat would be required to increase the temperature of
1 g
of water by
10
∘
C
?
Well, you'd need
4.18 J
to increase it by
1
∘
C
, another
4.18 J
to increase it by another
1
∘
C
, and so on. This means that you'd need
4.18 J
×
10
=
41.8 J
to increase the temperature of
1 g
of water by
10
∘
C
.
Now look at the value given to you. If you need
41.8 J
to increase the temperature of
1 g
of water by
10
∘
C
, what mass of water would require
10
times as much heat to increase its temperature by
10
∘
C
?
1 g
×
10
=
10 g
And that's your answer.
Mathematically, you can calculate this by using the equation
q
=
m
⋅
c
⋅
Δ
T
, where
q
- heat absorbed/lost
m
- the mass of the sample
c
- the specific heat of the substance
Δ
T
- the change in temperature, defined as final temperature minus initial temperature
Plug in your values to get
418
J
=
m
⋅
4.18
J
g
∘
C
⋅
(
20
−
10
)
∘
C
m
=
418
4.18
⋅
10
=
10 g
c. sulfuric acid, a liquid
b. hydrogen, a gas
d. water, a liquid
The substance that the molecules have the strongest attractions to one another is the sugar, a solid. The answer is letter A. The solid has a more definite shape and volume. The particles are locked into place. It cannot be further compressed due to the bond that exists between the molecules. The kinetic energy of the molecules is close to none because the molecules are so close and so compact with each other.
Answer:
a
Explanation:
b) 1 × 10^-6 g
c) 1000 g
d) 0.01 g
e) 0.001 g
f) 1 × 10^9 g
The (standard) unit of mass is gram. So, the complete name of each of the units is the name of the numerical value followed by the term "gram".
The complete names are:
In numerical representation of numbers, the meaning of the given numbers are:
deci
micro
kilo
centi
milli
giga
To complete the names, we simply add "gram" to the above representations. So, we have:
decigram
microgram
kilogram
centigram
milligram
gigagram
Read more about names of numerical values at: