Answer:
B 1650
Explanation:
If the colour of a solution turns pink on adding few drops of phenolphthalein indicator, it means solution is acidic. Select one :
True
False
Answer:
False, it becomes colourless in acidic solutions and turns pink in basic solutions
Which has more mass, 1 mole of magnesium or 1 mole of calcium?
Answer:
calcium has more mass
Explanation:
1 mole calcium mass= 40.078 g
1 mole magnesium mass= 24.305 g
When planning a simple experiment, what does it mean to “test one variable”?
a During the experiment, the scientist keeps the control the same but changes many other elements he or she is testing.
b During the experiment, the scientist has only one element, or variable, that is changed to test the hypothesis.
c The scientist can only use simple language and materials when planning the one variable to be tested.
d The scientist plans and performs just one science experiment a day to test one variable.
Answer:
I believe the answer is "b". "During the experiment, the scientist has only one element, or variable, that is changed to test the hypothesis."
Explanation:
I remember from last year but I'm not totally sure. Good luck!
The experimental setup has been the design that includes the experimental and the control group. during the experiment, only one variable is changed to test the hypothesis. Thus, option b is correct.
What is experimental design?The experiment design includes the testing of the hypothesis to solve the problem and reach the solution through the analysis of the observations. It has been the setup that includes the test and the control group that involves the dependent, independent, and controlled variables.
Testing one variable in the experimental designs means changing one of the elements of the experience to prove the reliability of the hypothesis. This variable is the factor that alters and affects the other factors of the experiment and leads to a cause and effect.
The result of the effect of the hypothesis proves the testability of the experiment and provides solutions to the research question. This further leads to the formulation of the law and theory.
Therefore, option A. testing one variable involves proving the hypothesis.
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Please help me l don’t understand please !!!!!!
Answer: C
Explanation:
he never had evidence in the first place that was nearly enough.
Paul swam 7 5/8 miles. His sister swam five times as many miles. How many miles did Paul's sister swim?
Answer:
Distance cover by Paul's sister by swim = 38.125 miles
Explanation:
Given:
Distance cover by Paul by swim = [tex]7\frac{5}{8}[/tex] = 61/8 miles
Distance cover by Paul's sister by swim = 5 times Distance cover by Paul
Find:
Distance cover by Paul's sister by swim
Computation:
Distance cover by Paul's sister by swim = 5 times Distance cover by Paul
Distance cover by Paul's sister by swim = 5 x [61 / 8 miles]
Distance cover by Paul's sister by swim = 305 / 8 miles
Distance cover by Paul's sister by swim = 38.125 miles
Determine the mass of hydrogen contained in 9.06 x 1024 H2O molecules.
Answer:
15.2 g H2
Explanation:
2H2O -> 2H2 + O2
9.06 x 10^24 molecules x (1 mol/6.022 x 10^23 molecules) x (2 mol H2/2 mol H2O) x (1.008 g/1 mol) = 15.2 g H2
Scientists have developed a new way to extract natural gas, called hydraulic fracturing, or fracking. Which of these is a positive impact of this method?
A. Decreased habitat
B. Decreased earthquakes
C. Increased supply
D. Increased demand
Answer:
The answer is C if its wrong you can report my answer I'm 100% sure its C
The tablets were crushed, and 4.9993 g of the powder was transferred to a beaker and reacted with HCl. After filtration, the filtrate was transferred to a 100-mL volumetric flask and diluted with water. 20.00 mL of this stock solution were combined with 0.2 M Na3PO4. The resulting precipitate weighed 0.3451 g after drying. Calculate the moles of BiPO4 precipitated, the moles of Bi3 in the stock solution, and the mass of BSS per tablet.
Answer:
Explanation:
From the information given:
Mass of BiPO₄ = 0.3451 g
Number of moles of BiPO₄ = [tex]0.3451 \ g \ BiPO_4 \times \dfrac{1 \ mol \ BiPO_4}{303.95 \ g \ BiPO_4}[/tex]
[tex]= 0.001135 \ mol[/tex]
The number of moles of Bi³⁺ in 20.00 mL is:[tex]= 0.001135 \ mol \ BiPO_4 \times \dfrac{1 \ mol \ of \ Bi^{3+}}{1 \ mol \ BiPO_4}[/tex]
= 0.001135 mol of Bi³⁺
The number of moles of Bi³⁺ in 100 mL stock solution
[tex]= 0.001135 \ mol \ Bi^{3+} \times \dfrac{100 \ mL}{20.0 \ mL}[/tex]
[tex]= 0.005675 \ mol[/tex]
Mass of BSS in 4.9993 g tablets
[tex]m = 0.005675 \ mol \ Bi^{3+} \times \dfrac{1 \ mol \ BSS}{1 \ mol \Bi^{3+}} \times \dfrac{362.1 \ g \ BSS}{1 \ mol \ BSS}[/tex]
m = 2.055 g BSS
Mass of BSS in 5.0103 g (5 tables)
[tex]m = 2.055 g \ BSS \times \dfrac{5.0103 \ g}{4.9993 \ g}[/tex]
= 2.06 g
∴
The mass of BSS per tablet is [tex]=\dfrac{2.06 \ g}{5 \ tablet}[/tex]
= 0.412 g BSS/ tablet
Of the following waves, which kind of wave does NOT require a medium?
a. light
b. water
с. ultrasound
d. sound
Calculate the pH of each solution:
0.030 M HBr
3.0 M HF
0.50 M HNO3
O.0010 M NaOH
0.150 M KOH
One of the reactions used to inflate automobile air bags involves sodium azide (NaN₃).
2NaN₃ --> 2Na + 3N₂
Determine the mass of N₂ produced from 250.0 g NaN₃
Answer:
161.54 g of N₂
Explanation:
The balanced equation for the reaction is given below:
2NaN₃ —> 2Na + 3N₂
Next, we shall determine the mass of NaN₃ that decomposed and the mass of N₂ produced from the balanced equation. This is illustrated below:
Molar mass of NaN₃ = 23 + (3×14)
= 23 + 42 = 65 g/mol
Mass of NaN₃ from the balanced equation = 2 × 65 = 130 g
Molar mass of N₂ = 2 × 14 = 28 g/mol
Mass of N₂ from the balanced equation = 3 × 28 = 84 g
SUMMARY:
From the balanced equation above,
130 g of NaN₃ decomposed to produce 84 g of N₂.
Finally, we shall determine the mass of N₂ produced by the decomposition of 250 g of NaN₃. This can be obtained as follow:
From the balanced equation above,
130 g of NaN₃ decomposed to produce 84 g of N₂.
Therefore, 250 g of NaN₃ will decompose to produce
= (250 × 84)/130 = 161.54 g of N₂
Thus, 161.54 g of N₂ were obtained from the reaction.
In the balanced equation-aPb(NO3)2(s)heatb PbO(s)+ c NO2(g)+ dO2(g); the values of a,b,c, d are respectively
Answer:
The balance reaction is
2Pb(NO3)2 ----》4NO2+2PbO+O2
hence the value of a,b,c,d are 2,4,2,1 respectively!
Plzzz help me plz I am timed!!
Answer:
Explanation:
pretty sure its gaillieo
Answer:
Galileo
Explanation:
he was the first one to use a telescope
As a future educator how will you handle a pupil who could possibly be a gifted child
Answer:
Learn how gifted students think. ...
Created tiered assignments for students. ...
Include a variety of levels in your classroom library. ...
Utilize their talents and interests. ...
Explore real-word application.
how many moles of ammonia can be formed from 4.0 mol H2
how many moles of hydrogen are required to form 8.0 mol NH3
how many moles of nitrogen are required to react with 6.0 mol H2
Answer: 1. 2.7 moles of ammonia are formed
2. 12.0 moles of hydrogen are required
3. 2.0 moles of nitrogen are required
Explanation:
The balanced chemical equation is:
[tex]N_2+3H_2\rightarrow 2NH_3[/tex]
According to stoichiometry:
3 moles of hydrogen form = 2 moles of ammonia
Thus 4.0 moles of hydrogen form =[tex]\frac{2}{3}\times 4.0=2.7moles[/tex] of ammonia
According to stoichiometry:
2 moles of ammonia are formed by = 3 moles of hydrogen
Thus 8.0 moles of ammonia are formed by =[tex]\frac{3}{2}\times 8.0=12.0moles[/tex] of hydrogen
According to stoichiometry:
3 moles of hydrogen react with = 1 mole of nitrogen
Thus 6.0 moles of hydrogen react with =[tex]\frac{1}{3}\times 6.0=2.0moles[/tex] of nitrogen
What is another name for heat?
A
light energy
B.
infrared energy
C
Thermal energy
D
electromagnetic energy
Answer:
C
Explanation:
thermal energy is the another name for heat
1. What do producers do, and what is another name for them?
Producers are the foundation of every food web in every ecosystem—they occupy what is called the first tropic level of the food web. The second trophic level consists of primary consumers—the herbivores, or animals that eat plants. At the top level are secondary consumers—the carnivores and omnivores who eat the primary consumers. Ultimately, decomposers break down dead organisms, returning vital nutrients to the soil, and restarting the cycle. Another name for producers is autotrophs, which means “self-nourishers.” There are two kinds of autotrophs. The most common are photoautotrophs—producers that carry out photosynthesis. Trees, grasses, and shrubs are the most important terrestrial photoautotrophs. In most aquatic ecosystems, including lakes and oceans, algae are the most important photoautotrophs.
What type of energy is being represented in the image
Answer:
Its Kinetic energy
Explanation:
You are giving the bow potential energy. "When you let the bow go, it returns to its original shape. The energy is transformed to kinetic energy and transferred to the arrow"
Answer:
potential
Explanation:
the energy is potential lol
At the same temperature and pressure, balloons of equal volume always contain
a.equal masses of gas.
b.equal numbers of molecules.
c.equal densities of gas.
d.equal numbers of atoms.
Answer:
B. equal numbers of molecules
Explanation:
What is the coefficient for hydrogen in the balanced equation for the reaction of solid tungsten(VI) oxide with gaseous hydrogen to form solid tungsten and liquid water?
Answer:
2
Explanation:
WO2(s) + 2H2(g) -> W(s) + 2H2O(l)
How many moles are in 15.2 grams of Calcium (Ca)?
Answer:
There are 0.379 moles of Ca in the given sample.
Explanation:
Hey there!
We're given that we have 15.2 grams of Ca (Calcium). We need to convert grams to moles.
There are many different conversion types for moles. A few examples are:
grams to molesmoles to gramsgrams to particlesmoles to litersThere are really endless possibilities for conversion factors. Since we want to find the number of moles in a certain sample, we first need to define what a mole is.
Mole - a unit of measurement in chemistryA mole is one unit of a certain item. For instance, one cup would be equivalent to one mole. Moles are simply a hypothetical unit in chemistry that act as a placeholder.
Now, how do we find the number of moles?
We know that a mole of something is one of that substance. In this case, we're referring to one atom of Calcium.
Therefore, we need to reference a periodic table to understand what the mass of one atom of calcium is equivalent to. I'll be using the official AP Chemistry periodic table as issued by the College Board.
When we reference the periodic table, we see the mass of one atom of calcium is equivalent to 40.08 amu (atomic mass units).
We learn in chemistry that we can use the terms amu and grams interchangeably, so we have learned that one mole of calcium is equivalent to 40.08 grams.
How do we work this out?
Now, we need to find out how many moles are in 15.2 grams of calcium. We can use dimensional analysis to work this out.
Our starting unit will be 15.2 grams of Ca.
[tex]\text{15.2 grams Ca}[/tex]We want to convert this into moles, so we need to cancel out our grams value. Additionally, since we know that we have 40.08 grams of Ca in one mole, we can set these up as two ratios:
[tex]\displaystyle \frac{\text{40.08 grams Ca}}{\text{1 mole Ca}}[/tex][tex]\displaystyle \frac{\text{1 mole Ca}}{\text{40.08 grams Ca}}[/tex]These ratios can be used to express the relationship between the moles of calcium and the mass of one calcium atom. However, we need our value of grams to cancel out, so since we will be using cross multiplication in our dimensional analysis, we need to use the ratio with grams on the bottom.
Now that we have selected our ratio, we can set up a multiplication problem of our two ratios:
[tex]\displaystyle \text{15.2 grams Ca} \times \frac{\text{1 mole Ca}}{\text{40.08 grams Ca}}[/tex]
We assume that we have a denominator of 1 below 15.2 grams Ca.
Now, we perform our multiplication.
[tex]\displaystyle \frac{\text{15.2 grams Ca} \ \times \ \text{1 mole Ca}}{\text{40.08 grams Ca}}[/tex]
We see that our remaining unit is going to be mole(s) Ca, so we can go ahead and drop our grams Ca unit.
[tex]\displaystyle \frac{\text{15.2} \ \times \ \text{1 mole Ca}}{\text{40.08}}[/tex]
Now, we need to simplify a little bit.
[tex]\displaystyle \frac{\text{15.2}}{\text{40.08}} = \text{? moles Ca}[/tex]
Finally, let's divide our fraction and evaluate our equation to find the value of moles Ca.
[tex]\displaystyle \frac{15.2}{40.08} = \text{0.379241517 moles Ca}[/tex]
Are we done yet?
Not just yet! To complete our work, we need to find the number of significant figures we can use. We are given two values in which we can use to judge how many significant figures we are limited to.
15.2 -- Three significant figures40.08 -- Four significant figuresIn chemistry, we always use the least number of significant figures for precision calculations, so we need to round our answer to three significant figures.
[tex]0.379241517 \approx 0.379[/tex]
Therefore, there are approximately 0.379 moles of Ca in the given sample.
Tam a highly reactive alkali metal in period 3 with only one valence electron
O Sodium (Na)
Beryllium (Be)
Magnesium (Mg)
Answer:
Sodium (Na)
Helium
Magnesium (Mg).
Explanation:
From the periodic table, we will understand that the group 1 metals are the alkali metal. However, the period runs from left to right on the periodic table while the group runs from up to down in the periodic table. In period 3, the alkali metal present there with one valence electron in its outermost shell is sodium (Na).
The only noble gas exists in the last group, group zero of the periodic table. However, the only noble gas with two electrons in its outermost shell is called Helium
The ALkaline earth metals are group 2 metals. They are usually shiny metals and the ability to lose 2 electrons in their outermost electron shell. The alkaline earth metal located in period 3 is Magnesium (Mg).
Which statement describes a homogeneous catalyst?
do
It is in a gaseous phase only. It is in the same phase as the reactants.
It is completely consumed by reactants.
It forms different products than the uncatalyzed reaction forms.
The statement which is given below describe a homogeneous catalyst.
"It is in the same phase as the reactants"
What is homogeneous catalyst?The catalyst which have similar phase to the reactant of the reaction is called homogeneous catalyst.
Mostly in homogeneous catalyst, catalyst present in liquid form.
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Plz help me I am timed!!!!!
Answer:
i think its the gibbous phase
Explanation:
A flask contains 1.45 moles of N2, 0.659 moles of He. If the total pressure is 775 torr, what is the partial pressure of O2 ?
Answer:
533.2 torr.
Explanation:
The following data were obtained from the question:
Mole of N₂ = 1.45 moles
Moles the He = 0.659 mole
Total pressure = 775 torr
Partial pressure of N₂ =?
Next, we shall determine the mole fraction of N₂. This can be obtained as follow:
Mole of N₂ = 1.45 moles
Moles the He = 0.659 mole
Total mole = 1.45 + 0.659 = 2.109 moles
Mole fraction of N₂ = Mole of N₂ / total mole
Mole fraction of N₂ = 1.45 / 2.109
Mole fraction of N₂ = 0.688
Gina, we shall determine the partial pressure of N₂. This can be obtained as follow:
Total pressure = 775 torr
Mole fraction of N₂ = 0.688
Partial pressure of N₂ =?
Partial pressure of N₂ = total pressure × mole fraction of N₂
Partial pressure of N₂ = 775 × 0.688
Partial pressure of N₂ = 533.2 torr.
Therefore, the partial pressure of N₂ is 533.2 torr.
Scientists classify organisms into three domains and six kingdoms. In which
kingdom are yeasts classified and why?
A Plantae, because they are eukaryotic.
B Protista, because they are prokaryotic.
Fungi, because they are heterotrophic.
Animalia, because they are autotrophic.
Answer:
c is correct option
according to the question.
Scientists classify organisms into three domains and six kingdoms. In Fungi kingdom are yeasts classified because they are heterotrophic. Therefore, option C is correct.
What do you mean by the term heterotrophic ?An organism is referred to be a heterotroph if it is unable to manufacture food on its own and must obtain it from other sources of organic carbon, primarily plant or animal materials.
All fungi are heterotrophic, which means they draw their energy from other living things.
Since they share some traits with fungi, such as the presence of chitin in their cell walls, extracellular digestion, saprophytic feeding, asexual reproduction by budding, and the ability to store food as glycogen, yeast cells are categorised as fungi.
Thus, option C is correct.
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Approximately 1 mL of two clear, colorless solutions, 0.1 M Ba(NO3)2 and 0.1 M Na2SO4, were combined. Upon mixing, a thick milky white precipitate formed. After centrifugation, the solution above the precipitate was found to be clear and colorless. Based on the these observations, determine if a reaction occurred. If so, what is the net ionic equation for the reaction.
Answer:
Ba²⁺(aq) + SO₄²⁻(aq) ⇒ BaSO₄(s)
Explanation:
Let's consider the molecular equation for the reaction between Ba(NO₃)₂ and Na₂SO₄. This is a double displacement reaction in which BaSO₄ forms a white precipitate.
Ba(NO₃)₂(aq) + Na₂SO₄(aq) ⇒ BaSO₄(s) + 2 NaNO₃(aq)
The complete ionic equation includes all the ions and insoluble species.
Ba²⁺(aq) + 2 NO₃⁻(aq) + 2 Na⁺(aq) + SO₄²⁻(aq) ⇒ BaSO₄(s) + 2 Na⁺(aq) + 2 NO₃⁻(aq)
The net ionic equation includes only the ions that participate in the reaction and insoluble species.
Ba²⁺(aq) + SO₄²⁻(aq) ⇒ BaSO₄(s)
The solubility of magnesium phosphate at a given temperature is 0.173 g/L. Calculate the Ksp at this temperature. After you calculate the Kspvalue, take the negative log and enter the (pKsp) value with 2 decimal places.
Answer: [tex]K_{sp}=1.25\times 10^{-14}[/tex]
[tex]pK_{sp}=13.90[/tex]
Explanation:
Solubility product is defined as the equilibrium constant in which a solid ionic compound is dissolved to produce its ions in solution. It is represented as [tex]K_{sp}[/tex]
The equation for the ionization of magnesium phosphate is given as:
[tex]Mg_3(PO_4)_2\rightarrow 3Mg^{2+}+2PO_4^{3-}[/tex]
When the solubility of [tex]Mg_3(PO_4)_2[/tex] is S moles/liter, then the solubility of [tex]Mg^{2+}[/tex] will be 3S moles\liter and solubility of [tex]PO_4^{3-}[/tex] will be 2S moles/liter.
Thus S = 0.173 g/L or [tex]\frac{0.173g/L}{262.8g/mol}=0.00065mol/L[/tex]
[tex]K_{sp}=(3S)^3\times (2S)^2[/tex]
[tex]K_{sp}=108S^5[/tex]
[tex]K_{sp}=108\times (0.00065)^5=1.25\times 10^{-14}[/tex]
[tex]pK_{sp}=-log(K_{sp})=\log (1.25\times 10^{-14})=13.90[/tex]
The value of Ksp and pKsp for the given reaction is 1.25 × 10⁻¹⁴ and 13.90 respectively.
How we calculate the Ksp?Solubility product constant (Ksp) is define as the product of the solubilities of the products, present in any chemical reaction.
Given chemical reaction will be represented as:
Mg₃(PO₄)₂ → 3Mg²⁺ + 2PO₄³⁻
Solubility of Mg₃(PO₄)₂ = 0.173 g/L or 0.173g/L / 262.8g/mole = 0.00065mol/L
Now for the given reaction let we consider that solubility of Mg₃(PO₄)₂ be x, solubility of Mg²⁺ be 3x and solubility of PO₄³⁻ will be 2x and equation for Ksp will be written as:
Ksp = [Mg²⁺]³[PO₄³⁻]²
Ksp = [3x]³[2x]²
Ksp = 108[x]⁵
Now we pot the solubility value of x as the solubility of Mg₃(PO₄)₂ & we get,
Ksp = 108(0.00065)⁵
Ksp = 1.25 × 10⁻¹⁴
Now we calculate the value of pKsp as:
pKsp = -log(Ksp)
pKsp = -log(1.25 × 10⁻¹⁴)
pKsp = -(-13.90) = 13.90
Hence value of pKsp is 13.90.
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Anyone know the answer
Answer:
b
Explanation:
i know
How many moles are in 272 grams of hydrogen peroxide (H2O2) ?
Answer:
8 moles
Explanation:
When we are asked to convert from grams of a substance into moles, we have to use the substance's molar mass.
Meaning that for this problem, we'll use the molar mass of hydrogen peroxide (H₂O₂), as follows:
272 g ÷ 34 g/mol = 8 molThere are 8 moles in 272 grams of hydrogen peroxide.