diff --git a/libscience/chemicaldataobject.cpp b/libscience/chemicaldataobject.cpp
--- a/libscience/chemicaldataobject.cpp
+++ b/libscience/chemicaldataobject.cpp
@@ -171,7 +171,7 @@
 
 void ChemicalDataObject::setType(int type)
 {
-    d->m_type = (ChemicalDataObject::BlueObelisk) type;
+    d->m_type = static_cast<ChemicalDataObject::BlueObelisk>(type);
 }
 
 QString ChemicalDataObject::unitAsString() const
diff --git a/libscience/isotope.cpp b/libscience/isotope.cpp
--- a/libscience/isotope.cpp
+++ b/libscience/isotope.cpp
@@ -94,7 +94,6 @@
 QString Isotope::abundance() const
 {
     return m_abundance.value().toString();
-    return QString();
 }
 
 double Isotope::halflife() const
diff --git a/libscience/parser.cpp b/libscience/parser.cpp
--- a/libscience/parser.cpp
+++ b/libscience/parser.cpp
@@ -107,7 +107,7 @@
 
     // The integer.
     while (isdigit(m_nextChar)) {
-        result = result * 10.0 + (double)(m_nextChar - '0');
+        result = result * 10.0 + static_cast<double>(m_nextChar - '0');
         getNextChar();
     }
     *_result = result;
@@ -119,7 +119,7 @@
 
     double  decimal = 0.1;
     while (isdigit(m_nextChar)) {
-        result += decimal * (double)(m_nextChar - '0');
+        result += decimal * static_cast<double>(m_nextChar - '0');
         decimal /= 10.0;
         getNextChar();
     }
diff --git a/libscience/spectrum.cpp b/libscience/spectrum.cpp
--- a/libscience/spectrum.cpp
+++ b/libscience/spectrum.cpp
@@ -95,7 +95,7 @@
     foreach (Spectrum::peak *p, m_peaklist) {
         double newInt = p->intensity * 1000 / maxInt;
 
-        p->intensity = (int)qRound(newInt);
+        p->intensity = qRound(newInt);
     }
 }
 
diff --git a/src/calculator/calculator.cpp b/src/calculator/calculator.cpp
--- a/src/calculator/calculator.cpp
+++ b/src/calculator/calculator.cpp
@@ -86,7 +86,7 @@
 
 void calculator::slotItemSelection(QTreeWidgetItem *item)
 {
-    if (item == 0L) {
+    if (item == nullptr) {
         return;
     }
 
diff --git a/src/calculator/concCalculator.cpp b/src/calculator/concCalculator.cpp
--- a/src/calculator/concCalculator.cpp
+++ b/src/calculator/concCalculator.cpp
@@ -288,15 +288,15 @@
     case 1:     // cannot be calculated (insufficient data)
         error(INSUFFICIENT_DATA_MOLE);
         return;
-        break;
+
     case 2:     // molality specified
         numMoles = massSolvent() / 1000.0 * m_concentration;
         break;
     case 3:     // cannot be calculated (insufficient data)
     case 4:
         error(INSUFFICIENT_DATA_MOLE);
         return;
-        break;
+
     case 5:     // mole fraction specified
         numMoles = m_concentration / (100.0 - m_concentration) * molesSolvent();
         break;
@@ -328,7 +328,7 @@
     case 0: // molarity not sufficient
         error(INSUFFICIENT_DATA_EQT);
         return;
-        break;
+
     case 1: // normality specified
         numEqts = volumeSolvent() * m_concentration;
         break;
@@ -338,7 +338,7 @@
     case 5:
         error(INSUFFICIENT_DATA_EQT);
         return;
-        break;
+
     }
 
     if (type2 == 2) {    // Amount of solute specified in moles, cannot calculate
@@ -368,8 +368,8 @@
     case 3:         // mass fraction specified
     case 4:         // volume fraction specified
         error(INSUFFICIENT_DATA_SOLVENT);
-        return;
-        break;      // cannot be calculated (insufficient data)
+        return;   // cannot be calculated (insufficient data)
+
     case 5:         // mole fraction specified
         numMoles = (100.0 - m_concentration) / m_concentration * molesSolute();
         break;
@@ -623,6 +623,7 @@
         break;
     case 2:
         volume = massSolute() / densitySolute();
+        break;
     default:
         volume = 0;
         break;
diff --git a/src/calculator/gasCalculator.cpp b/src/calculator/gasCalculator.cpp
--- a/src/calculator/gasCalculator.cpp
+++ b/src/calculator/gasCalculator.cpp
@@ -334,7 +334,5 @@
         break;
     case GAS_MOLAR_MASS_ZERO:
         ui.error->setText(i18n("Molar mass cannot be zero, please enter a non-zero value."));
-    default:
-        break;
     }
 }
diff --git a/src/detailinfodlg.cpp b/src/detailinfodlg.cpp
--- a/src/detailinfodlg.cpp
+++ b/src/detailinfodlg.cpp
@@ -164,7 +164,7 @@
     DOM::HTMLElement element = htmlpart->htmlDocument().body();
     if (element.tagName() == "body") {
         const QColor backgroundColor = palette().background().color();
-        ((DOM::HTMLBodyElement)element).setBgColor(backgroundColor.name());
+        (static_cast<DOM::HTMLBodyElement>(element)).setBgColor(backgroundColor.name());
     }
 
     htmlpart->end();
diff --git a/src/exportdialog.cpp b/src/exportdialog.cpp
--- a/src/exportdialog.cpp
+++ b/src/exportdialog.cpp
@@ -179,16 +179,18 @@
 {
     *m_outputStream << HTML_HEADER << "<table>\n";
     foreach (QListWidgetItem *element, ui.elementListWidget->selectedItems()) {
+        ElementListEntry* element_entry = static_cast <ElementListEntry*> (element);
+
         *m_outputStream << "<tr>\n<th colspan=\"2\">"
-        << ((ElementListEntry*)element)->m_element->dataAsString(ChemicalDataObject::name)
+        << element_entry->m_element->dataAsString(ChemicalDataObject::name)
         << "</th>\n</tr>\n";
         foreach (QListWidgetItem *property, ui.propertyListWidget->selectedItems()) {
+            PropertyListEntry* property_entry = static_cast<PropertyListEntry*> (property);
+
             *m_outputStream << "<tr>\n<td class=\"property\">"
-            << ((PropertyListEntry*) property)->text()
+            << property_entry->text()
             << "</td>\n<td class=\"value\">"
-            << KalziumUtils::prettyUnit(
-                ((ElementListEntry*) element)->m_element,
-                ((PropertyListEntry*) property)->m_type)
+            << KalziumUtils::prettyUnit(element_entry->m_element,property_entry->m_type)
             << "</td>\n</tr>\n";
         }
     }
@@ -199,16 +201,18 @@
 {
     *m_outputStream << XML_HEADER << "<elements>\n";
     foreach (QListWidgetItem *element, ui.elementListWidget->selectedItems()) {
+        ElementListEntry* element_entry = static_cast<ElementListEntry*> (element);
+
         *m_outputStream << "  <element name=\""
-        << ((ElementListEntry*) element)->m_element->dataAsString(ChemicalDataObject::name)
+        << element_entry->m_element->dataAsString(ChemicalDataObject::name)
         << "\">\n";
         foreach (QListWidgetItem *property, ui.propertyListWidget->selectedItems()) {
+            PropertyListEntry* property_entry = static_cast<PropertyListEntry*> (property);
+
             *m_outputStream << "    <property name=\""
-            << ((PropertyListEntry*) property)->text()
+            << property_entry->text()
             << "\">"
-            << KalziumUtils::prettyUnit(
-                ((ElementListEntry*) element)->m_element,
-                ((PropertyListEntry*) property)->m_type)
+            << KalziumUtils::prettyUnit(element_entry->m_element,property_entry->m_type)
             << "</property>\n";
         }
         *m_outputStream << "  </element>\n";
@@ -220,20 +224,25 @@
 {
     *m_outputStream << "Name";
     foreach (QListWidgetItem *property, ui.propertyListWidget->selectedItems()) {
+        PropertyListEntry* property_entry = static_cast<PropertyListEntry*> (property);
+
         *m_outputStream << ", \""
-        << ((PropertyListEntry*) property)->text()
+        << property_entry->text()
         << "\"";
     }
+
     *m_outputStream << "\n";
     foreach (QListWidgetItem *element, ui.elementListWidget->selectedItems()) {
+        ElementListEntry* element_entry = static_cast<ElementListEntry*> (element);
+
         *m_outputStream << "\""
-        << ((ElementListEntry*) element)->m_element->dataAsString(ChemicalDataObject::name)
+        << element_entry->m_element->dataAsString(ChemicalDataObject::name)
         << "\"";
         foreach (QListWidgetItem *property, ui.propertyListWidget->selectedItems()) {
+            PropertyListEntry* property_entry = static_cast<PropertyListEntry*> (property);
+
             *m_outputStream << ", \""
-            << KalziumUtils::prettyUnit(
-                ((ElementListEntry*) element)->m_element,
-                ((PropertyListEntry*) property)->m_type)
+            << KalziumUtils::prettyUnit(element_entry->m_element,property_entry->m_type)
             << "\"";
         }
         *m_outputStream << "\n";
diff --git a/src/gradientwidget_impl.cpp b/src/gradientwidget_impl.cpp
--- a/src/gradientwidget_impl.cpp
+++ b/src/gradientwidget_impl.cpp
@@ -63,8 +63,8 @@
     double dblMin = elementProperty->gradient()->minValue();
 
     // saving the decimals in the int
-    const int intMax = dblMax * MULTIPLIKATOR;
-    const int intMin = dblMin * MULTIPLIKATOR;
+    const int intMax = static_cast<int>(dblMax * MULTIPLIKATOR);
+    const int intMin = static_cast<int>(dblMin * MULTIPLIKATOR);
 
     // now we have the slider numbers, so put the speed to a adequate value.
     Speed->setMaximum(intMax / 100);
@@ -112,7 +112,7 @@
     gradient_slider->blockSignals(true);
 
     // setting the decimals in int
-    int intvar = doubleVar * MULTIPLIKATOR;
+    int intvar = static_cast<int>(doubleVar * MULTIPLIKATOR);
 
     gradient_slider->setValue(intvar);
 
diff --git a/src/isotopetable/isotopeguideview.cpp b/src/isotopetable/isotopeguideview.cpp
--- a/src/isotopetable/isotopeguideview.cpp
+++ b/src/isotopetable/isotopeguideview.cpp
@@ -24,7 +24,7 @@
 
 IsotopeGuideView::IsotopeGuideView(QWidget *parent) : QGraphicsView(parent)
 {
-    m_guidedView = 0;
+    m_guidedView = nullptr;
     m_scale = 1.0;
 
     setCursor(Qt::OpenHandCursor);
diff --git a/src/kdeeduglossary.cpp b/src/kdeeduglossary.cpp
--- a/src/kdeeduglossary.cpp
+++ b/src/kdeeduglossary.cpp
@@ -232,19 +232,19 @@
     QStringList reflist;
 
     itemList = itemDocument.elementsByTagName("item");
+    const int num = itemList.count();
 
-    const uint num = itemList.count();
-    for (uint i = 0; i < num; ++i) {
+    for (int i = 0; i < num; ++i) {
         reflist.clear();
         GlossaryItem *item = new GlossaryItem();
 
-        itemElement = (const QDomElement&) itemList.item(i).toElement();
+        itemElement = itemList.item(i).toElement();
 
         QDomNode nameNode = itemElement.namedItem("name");
         QDomNode descNode = itemElement.namedItem("desc");
 
         QString picName = itemElement.namedItem("picture").toElement().text();
-        QDomElement refNode = (const QDomElement&) itemElement.namedItem("references").toElement();
+        QDomElement refNode = itemElement.namedItem("references").toElement();
 
         QString desc = i18n(descNode.toElement().text().toUtf8());
         if (!picName.isEmpty()) {
diff --git a/src/molcalcwidget.cpp b/src/molcalcwidget.cpp
--- a/src/molcalcwidget.cpp
+++ b/src/molcalcwidget.cpp
@@ -98,7 +98,7 @@
             for (i = 0; i < length; ++i) {
                 shortForm = shortList.takeFirst ();
                 fullForm = fullList.takeFirst ();
-                ui.user_defined->setItem((int)i, 0, new QTableWidgetItem
+                ui.user_defined->setItem(i, 0, new QTableWidgetItem
                     (i18n("%1",shortForm + " : " + fullForm)));
             }
         } else {
@@ -134,7 +134,7 @@
             for (i = 0; i < length; ++i) {
                 shortForm = shortList.takeFirst();
                 fullForm = fullList.takeFirst();
-                ui.pre_defined->setItem((int)i, 0, new QTableWidgetItem
+                ui.pre_defined->setItem(i, 0, new QTableWidgetItem
                     (i18n("%1",shortForm + " : " + fullForm)));
             }
         } else {
diff --git a/src/orbitswidget.cpp b/src/orbitswidget.cpp
--- a/src/orbitswidget.cpp
+++ b/src/orbitswidget.cpp
@@ -239,8 +239,8 @@
         DC.setPen(Qt::NoPen);
 
         for (int e = 0; e < *it; ++e) {
-            int x = (int)translateToDX(d / 2.0, (double)e, *it);
-            int y = (int)translateToDY(d / 2.0, (double)e, *it);
+            int x = static_cast <int> (translateToDX(d / 2.0, static_cast <double> (e), *it));
+            int y = static_cast <int> (translateToDY(d / 2.0, static_cast <double> (e), *it));
 
             //Creating a gradient for the current electron.
             QRadialGradient grad(QPointF(x + mx + d / 2 - r_electron / 2, y + my + d / 2 - r_electron / 2), r_electron);
diff --git a/src/spectrumviewimpl.cpp b/src/spectrumviewimpl.cpp
--- a/src/spectrumviewimpl.cpp
+++ b/src/spectrumviewimpl.cpp
@@ -72,8 +72,7 @@
 
         QStringList row = QStringList() << QString::number(peakWavelength)
                           << QString::number(peak->intensity);
-
-        items.append(new QTreeWidgetItem((QTreeWidget*)0, row));
+        items.append(new QTreeWidgetItem(static_cast <QTreeWidget*> (nullptr), row));
     }
     peakListTable->insertTopLevelItems(0, items);
 }
diff --git a/src/spectrumwidget.cpp b/src/spectrumwidget.cpp
--- a/src/spectrumwidget.cpp
+++ b/src/spectrumwidget.cpp
@@ -152,7 +152,7 @@
     wavelength = KUnitConversion::Value(wavelength,KUnitConversion::UnitId(Prefs::spectrumWavelengthUnit()))
                  .convertTo(KUnitConversion::Nanometer).number();
 
-    int wavelength_ = (int)floor(wavelength);
+    int wavelength_ = static_cast <int> (floor(wavelength));
 
     if (wavelength_ < 380 || wavelength_ > 780) {
         return QColor(Qt::white);
@@ -203,7 +203,7 @@
         return 0;
     } else {
 //         return qRound(m_intensityMax * pow(color*factor, m_gamma)); FIXME
-        return m_intensityMax * color;
+        return static_cast <int> (m_intensityMax * color);
     }
 }
 
@@ -216,7 +216,7 @@
     const int d = 10;
 
     //the total number of tickmarks to draw (small and long)
-    const int numberOfTickmarks = (int)floor((double)(width() / d));
+    const int numberOfTickmarks = static_cast <int> (floor(width() / d));
 
     double pos = 0.0;
 
@@ -227,7 +227,7 @@
             if (i % 10 == 0 &&
                 i * d > space &&
                 i * d < width() - space) {
-                pos = (double)(i * d) / width();
+                pos = static_cast <double> (i * d) / width();
                 p->fillRect(i * d - space, m_realHeight + 12, 2 * space, 15, Qt::white);
                 p->drawText(i * d - space, m_realHeight + 12, 2 * space, 15, Qt::AlignCenter,
                             QString::number(KalziumUtils::strippedValue(Wavelength(pos))));
@@ -315,13 +315,13 @@
         resetSpectrum();
     }
 
-    findPeakFromMouseposition(Wavelength((double)e->pos().x() / width()));
+    findPeakFromMouseposition(Wavelength(static_cast <double> (e->pos().x()) / width()));
 }
 
 void SpectrumWidget::findPeakFromMouseposition(double wavelength)
 {
     qDebug() << "SpectrumWidget::findPeakFromMouseposition()";
-    Spectrum::peak *peak = NULL;
+    Spectrum::peak *peak = nullptr;
 
     //find the difference in percent (1.0 is 100%, 0.1 is 10%)
     double dif = 0.0;
@@ -358,8 +358,8 @@
 void SpectrumWidget::mouseReleaseEvent(QMouseEvent *e)
 {
     if (e->button() == Qt::LeftButton) {
-        int left = (int)Wavelength((double)m_LMBPointPress.x() / width());
-        int right = (int)Wavelength((double)e->pos().x() / width());
+        int left = static_cast <int> (Wavelength(m_LMBPointPress.x()) / width());
+        int right = static_cast <int> (Wavelength(e->pos().x()) / width());
 
         if (left == right) {
             return;
diff --git a/src/tablesdialog.cpp b/src/tablesdialog.cpp
--- a/src/tablesdialog.cpp
+++ b/src/tablesdialog.cpp
@@ -267,7 +267,7 @@
 
 void MyTableWidget::contextMenuEvent(QContextMenuEvent* event)
 {
-    QMenu* menu = new QMenu((QWidget*) sender());
+    QMenu* menu = new QMenu(static_cast <QWidget*> (sender()));
     menu->addAction(i18n("&Copy"), this, SLOT(copyToClipboard()), QKeySequence(Qt::Key_C | Qt::CTRL));
     menu->exec(event->globalPos());
 }
diff --git a/src/tools/moleculeview.cpp b/src/tools/moleculeview.cpp
--- a/src/tools/moleculeview.cpp
+++ b/src/tools/moleculeview.cpp
@@ -171,7 +171,7 @@
     m_molecule = *IoWrapper::readMolecule(filename);
 
     if (m_molecule.atomCount() != 0) {
-        disconnect(ui.glWidget->molecule(), 0, this, 0);
+        disconnect(ui.glWidget->molecule(), nullptr, this, nullptr);
         ui.glWidget->setMolecule(&m_molecule);
         ui.glWidget->update();
         slotUpdateStatistics();
diff --git a/src/tools/obconverter.cpp b/src/tools/obconverter.cpp
--- a/src/tools/obconverter.cpp
+++ b/src/tools/obconverter.cpp
@@ -61,7 +61,7 @@
 KOpenBabel::~KOpenBabel()
 {
     delete OBConvObject;
-    OBConvObject = NULL;
+    OBConvObject = nullptr;
 }
 
 void KOpenBabel::setupWindow()